If you want to add a game to the list / recommend a listed game at a current price / advise against buying any of the listed games - simply leave a comment.

I will only list games that are not listed on the steam main sale page.

EDIT: Games are now sorted alphabetically. Added section for Daily deals so that they stand out more.
EDIT2: Added bundle counter to every listed game, you can basically search for non bundled games using search function in your browser, looking for phrase: NOT BUNDLED BEFORE. However, note that I checked the bundle counter against Isthereanydeal.com and not Steamgifts bundle list, which includes non-bundled free/heavily discounted games as well as bundled ones.
EDIT3: Divided the deals into Individual games and DLCs and Game packs and bundles. Also added Giveaways section, where I might post giveaways if I create some, because why the hell not.

Daily Deals List:

Individual Games and DLCs:

• OVER Anno 1404 -75%, 2.49€, 95% positive reviews, NOT BUNDLED BEFORE - lowest recorded price for the Steam version
• OVER Broken Sword 4 - the Angel of Death -80%, 1.99€, 51% positive reviews, NOT BUNDLED BEFORE - The 1-3 parts can be bought as a bundle (mentioned in the Game Packs and Bundles section)
• OVER Dungeon Defenders -90%, 1.49€, 93% positive reviews, bundled: 4
• OVER ENSLAVED™: Odyssey to the West™ Premium Edition -75%, 4.99€, 87% positive reviews, NOT BUNDLED BEFORE
• OVER Gas Guzzlers Extreme: Full Metal Zombie -75%, 2.47€, 86% positive reviews, NOT BUNDLED BEFORE - A fun looking DLC to the Guz Guzzlers game
• OVER Hotline Miami -85%, 1.27€, 97% positive reviews, bundled: 4 - if you don't have it yet, you need it
• OVER Legend of Grimrock -85%, 2.24€, 95% positive review, bundled: 3
• BACK FOR ENCORE! METAL GEAR RISING: REVENGEANCE -75%, 4.99€, 92% positive reviews, NOT BUNDLED BEFORE
• OVER Nidhogg -90%, 1.39€, 88% positive reviews, NOT BUNDLED BEFORE - Was in the main list, appeared as a daily deal
• OVER PixelJunk Eden -90%, 0.69€, 83% positive reviews, bundled: 4
• OVER PixelJunk Shooter -90%, 0.89€, 91% positive reviews, bundled: 5
• OVER Rayman Origins -75%, 2.49€, 96% positive reviews, NOT BUNDLED BEFORE
• OVER RollerCoaster Tycoon: Deluxe -75%, 1.14€, 97% positive reviews, NOT BUNDLED BEFORE
• OVER Sir, you are being hunted -90%, 1.99€, 85% positive reviews, NOT BUNDLED BEFORE

Game Packs and Bundles

• OVER Broken Sword Trilogy -80%, 1.39€, 3 games ranging from 53% to 91% positive reviews, bundled: 2
• OVER Crysis Collection -78%, 8.79€, 3 games ranging from 81% to 88% positive reviews, NOT BUNDLED BEFORE - Only Crysis 2 is featured as the minigame unlock, while the other parts of the series are discounted as well
• BACK FOR ENCORE! Metro Redux Bundle -80%, 7.99€, 86% & 88% positive reviews, NOT BUNDLED BEFORE - A sweet deal
• BACK FOR ENCORE Telltale Collection -66%, 56.77€, 23 games ranging from 64% to 98% positive reviews, NOT BUNDLED BEFORE

All Sale Long Deals List:

Individual Games and DLCs:

• A.R.E.S.: Extinction Agenda -90%, 0.99€, 70% positive reviews, bundled: 4
• Advent Rising -80%, 1.99€, 90% positive reviews, NOT BUNDLED BEFORE
• ARMA: Gold Edition -80%, 1.59€, 72% positive reviews, bundled: 1
• Before the Echo (known before as Sequence) -75%, 0.99€, 86% positive reviews, bundled: 3
• Blade Kitten -75%, 1.49€, 88% positive reviews, NOT BUNDLED BEFORE
• Bloody Trapland -90%, 0.99€, 90% positive reviews, bundled: 1
• Chivalry: Medieval Warfare -80%, 3.39€, 87% positive reviews, bundled: 1
• Collapse -80%, 3.99€, 72% positive reviews, NOT BUNDLED BEFORE
• Corporate Lifestyle Simulator -75%, 1.24€, 88% positive reviews, bundled: 1 - Just a small game to blow off some Steam
• Contraption Maker -85%, 1.04€, 94% positive reviews, bundled: 2
• Cortex Command -75%, 4.74€, 78% positive reviews, bundled: 2
• Dark Horizons: Mechanized Corps -33%, 10.04€, 86% positive reviews, NOT BUNDLED BEFORE - Early Access mech game, only a few reviews, but mostly positive ones.
• The Darkness II -80%, 5.59€, 91% positive reviews, bundled: 2 - Daily sale passed, the price stayed
• Darkstar One -75%, 1.49€, 83% positive reviews, NOT BUNDLED BEFORE
• Day of Defeat: Source -75%, 1.74€, 92% positive reviews, NOT BUNDLED BEFORE - Looks like people still play this
• Deadly Premonition: Director's Cut -90%, 2.49€, 72% positive reviews, bundled: 5
• Depth -60%, 9.19€, 91% positive reviews, NOT BUNDLED BEFORE - lowest recorded cut on this quite fresh out of EA game
• Depths of Fear :: Knossos -80%, 1.19€, 71% positive reviews, bundled: 2
• DETOUR -96%, 0.19€, 72% positive reviews, bundled: 1
• Door Kickers -60%, 7.59€, 97% positive reviews, NOT BUNDLED BEFORE - quite a good deal for the Steam version
• Double Dragon: Neon -80%, 1.99€, 83% positive reviews, bundled: 2
• Duck Games -23%, 10€, 97% positive reviews, NOT BUNDLED BEFORE - Brand new game, already discounted, quite popular, great reviews ratio, what's not to like?
• Eador: Masters of the Broken World -80%, 3.79€, 66% positive reviews, bundled: 4
• Edna & Harvey: Harvey's New Eyes -95%, 0.64€, 93% positive reviews, bundled: 6
• Eldritch -87%, 1.55€, 89% positive reviews, bundled: 2
• Enemy Mind -90%, 0.99€, 92% positive reviews, bundled: 4
• Ether One -75%, 4.99€, 84% positive reviews, NOT BUNDLED BEFORE
• Fait Strike -35%, 2.59€, 80% positive reviews, NOT BUNDLED BEFORE - -35% might seem as a bit of a low discount, however, it's actually the lowest price recorded
• Fancy Skulls -50%, 3.49€, 94% positive reviews, bundled: 3 - 50% on a promising EA game. I guess that's a good deal
• Fly'N -70%, 2.99€, 87% positive reviews, bundled: 7
• Ford Racing 3 -85%, 0.74€, 85% positive reviews, NOT BUNDLED BEFORE - used to play this long time ago and it was fun. Not sure if it could withstand the test of time, though.
• The Forest of Doom -70%, 2.99€, 81% positive reviews, bundled: 2 - Choose your own adventure type of game, lowest price recorded so far.
• Full Bore -66%, 5.09€, 86% positive reviews, bundled: 3
• Glare -75%, 2.24€, 87% positive reviews, NOT BUNDLED BEFORE - Pretty charming art style.
• GTGD S1: More than a Gamer -75%, 0.49€, 86% positive reviews, NOT BUNDLED BEFORE - guides for Unity 3D, bought it for myself because they might come useful some day
• Guacamelee! Gold Edition / Guacamelee! Super Turbo Championship Edition -75%, 3.24€/3.49€, 94%/96% positive reviews, bundled:2/4
• Gun Metal -85%, 1.34€, 74% positive reviews, bundled: 12
• Half Minute Hero: The Second Coming -75%, 2.49€, 96% positive reviews, bundled: 1 - Probably getting that later on
• Hard Truck Apocalypse -66%, 2.71€, 69% positive reviews, NOT BUNDLED BEFORE - The execution might not be top-notch, however, the concept seems pretty interesting.
• Hatoful Boyfriend -75%, 1.99€, 94% positive reviews, bundled: 2 - Notice me, (bird) senpai! If you're not afraid of getting caught playing this, then go ahead, I guess...
• Hero Siege - 75%, 1.49€, 82% positive reviews - Bundled many times, but if someone still wants that, it's a good grab
• Hive - 75%, 2.49€, 96% positive reviews, NOT BUNDLED BEFORE - Port of a real life board game.
• How to Survive -90%, 1.39€ (1.89€ with DLCs), 84% positive reviews, bundled: 1 (Storm edition NOT BUNDLED BEFORE) - I didn't really like the game, but it's entertaining for some time, so it might be worth grabbing at this price
• Ichi -90%, 0.49€, 90% positive reviews, bundled: 9
• Journal -80%, 1.99€, 81% positive reviews, NOT BUNDLED BEFORE
• Journey of the Roach -95%, 0.74€, 87% positive reviews, bundled: 3 - Point&click from Daedalic, they know how to make those
• KAMI -75%, 0.99€, 95% positive reviews, bundled: 3 - Bundled many times, but somehow I missed all of the opportunities
• The Last Tinker™: City of Colors -70%, 5.99€, 90% positive reviews, bundled: 1
• L.A. Noire -70%, 4.49€, 89% positive reviews, NOT BUNDLED BEFORE
• Left 4 Dead 2 -80%, 2.79€, 97% positive reviews, NOT BUNDLED BEFORE
• Lichdom: Battlemage -80%, 7.39€, 67% positive reviews, NOT BUNDLED BEFORE
• Lili: Child of Geos -80%, 1.99€, 89% positive reviews, bundled: 1 - The art style looks nice, haven't heard of the game before. Might be a time to check it out.
• LISA -50%, 4.99€, 98% positive reviews, NOT BUNDLED BEFORE - not sure what kind of game this is, but 98% PR speaks to me
• LYNE -70%, 0.89€, 97% positive reviews, bundled: 4 - "Relaxing puzzle game with infinte gameplay through randomly generated daily sets" abun4i
• McDROID -50%, 9.99€, 78% positive reviews, NOT BUNDLED BEFORE - "McDROID, it's pretty hilarious for a tower defence and I liked the design" TheRivalSword
• Marauder -70%, 2.99, 63% positive reviews, NOT BUNDLED BEFORE - "A RPG all about good tactics and survival in a post-Nuclear war Russia." KenOD
• Merchants of Kaidan -75%, 3.74€, 69% positive reviews, bundled: 1 - "Addictive but buggy, don't buy at full price but snap it up in a deal." Mancomb Seepgood, most rated review on Steam
• Miasmata -80%, 2.99€, 81% positive reviews, bundled: 1
• Millie -85%, 0.59€, 79% positive reviews, bundled: 2
• Mini Ninjas -75%, 2.49€, 88% positive reviews, bundled: 1
• Morphopolis -96%, 0.19€, 84% positive reviews, bundled: 1 - Looks nice, dirt cheap, why not?
• MouseCraft -70%, 3.89€, 90% positive reviews, bundled: 1 - list Bad rats, but actually good.
• Munin -90%, 0.99€, 81% positive reviews, bundled: 1 - lowest price recorded so far
• Nidhogg -80%, 2.79€ (2.30€ if you buy a 2-pack), 88% positive reviews, NOT BUNDLED BEFORE - I've heard it's great fun for local coop, might grab it later on
• Nimbus -75%, 2.49€, 97% positive reviews, bundled: 1 - looks promising and fun
• OMG Zombies -90%, 0.49€, 82% positive reviews, bundled: 1
• One Way Heroics -75%, 0.74€, 96% positive reviews, bundled: 2
• Orbital Gear -90%, 0.69€, 85% positive reviews, bundled: 3
• Our Darker Purpose -80%, 2.99, 82% positive reviews, bundled: 1 - "A great game and some interesting lore and artstyle. But be prepared, this game is a bit harder than your usual game." Adelion
• Outland -80%, 1.99€, 90% positive reviews, NOT BUNDLED BEFORE - This art style looks great.
• Out there somewhere -96%, 0.19€, 92% positive reviews, bundled: 3
• Phoenix Force -86%, 0.97€, 85% positive reviews, bundled: 2
• Pool Nation -90%, 0.99€, 91% positive reviews, bundled: 6 - Bundled many times, but it's a good opportunity to snag it if you've missed it
• Primal Carnage -80%, 2.49€, 84% positive reviews, bundled: 3 - Dinosaur hunting, yum! It's speculated to be better than its sequel.
• Primordia -70%, 2.99€, 97% positive reviews, bundled: 2
• Quantum Conundrum -75%, 2.24€, 85% positive reviews, NOT BUNDLED BEFORE - A funny FP puzzle game, definitely looks cool!
• Qbeh-1: The Atlas Cube -75%, 2.24€, 93% positive reviews, bundled: 1 - lowest price recorded so far
• Retro/Grade -95%, 0.49€, 87% positive reviews, bundled: 7
• Rise of Venice -75%, 7.49€, 55% positive reviews, NOT BUNDLED BEFORE
• Rochard -85%, 1.34€, 92% positive reviews, bundled: 3
• RollerCoaster Tycoon: Deluxe -65%, 1.60€, 97% positive reviews, NOT BUNDLED BEFORE - waiting for a flash/daily sale, but I guess it won't be featured there as it's kinda old
• Sanitarium -50%, 3.99€, 93% positive reviews, NOT BUNDLED BEFORE - "... One of the best point and click/puzzle adventures I've ever played." Erynion
• Saturday Morning RPG -85%, 1.04€, 82% positive reviews, bundled: 5
• Shadow Warrior -85%, 3.74€, 95% positive reviews, bundled: 1 - Not the lowest recorded, but still a solid discount on a solid game
• Shadowgate (2014) -75%, 3.74€, 93% positive reviews, bundled: 1
• Shadowrun: Dragonfall - Director's Cut -70%, 4.49€, 94% positive reviews, NOT BUNDLED BEFORE
• Shantae: Risky's Revenge -75%, 2.49€, 92% positive reviews, bundled: 1 - Metroidvania platformer
• Shattered Planet -75%, 2.74€, 74% positive reviews, bundled: 1
• Sledgehammer / Gear Grinder -80%, 1.59€, 70% positive reviews, NOT BUNDLED BEFORE
• Soul Gambler -90%, 0.39€, 75% positive reviews, bundled: 4
• Space Rangers HD: A War Apart -75%, 2.74€, 95% positive reviews, bundled: 1 - Bam, sold.
• Stranded Deep -34%, 9.89€, 91% positive reviews, NOT BUNDLED BEFORE - First recorded discount on this promising EA game
• Tales of Monkey Island Complete Pack -75%, 7.99€, 91%, NOT BUNDLED BEFORE - Sequel to a great series. Also lowest recorded price of the Steam version.
• Toybox Turbos -75%, 3.74€, 85% positive reviews, NOT BUNDLED BEFORE
• Ultimate General: Gettysburg -60%, 4.79€, 91% positive reviews, NOT BUNDLED BEFORE - lowest recorded price so far
• Unstoppable Gorg -90%, 0.99€, 78% positive reviews, bundled: 3
• Urban Trials Freestyle -90%, 0.99€, 79% positive reviews, bundled: 2
• Violett -80%, 1.99€, 61% positive reviews, bundled:1
• Waveform -96%, 0.19€, 85% positive reviews, bundled: 2 - This was at 95% discount some time ago, so some people probably have it
• Wyv and Keep -81%, 2.84€, 100% positive reviews, NOT BUNDLED BEFORE - copied from the previous thread
• Yet Another Zombie Defense -75%, 0.49€, 87% positive reviews, bundled: 1
• Zigfrak -60%, 1.99€, 79% positive reviews, bundled: 3

Game Packs and Bundles

• 2k 10th Anniversary Collection -87%, 45.73€, 21 games ranging from 67% to 97% positive reviews, NOT BUNDLED BEFORE - if you really lack most of the games here, this makes a great purchase
• Avernum Bundle -90%, 0.85€, 3 games ranging from 75% to 90% positive reviews, NOT BUNDLED BEFORE - This and more is included in the Spiderweb Software Complete Pack mentioned below
• Commandos Collection -90%, 1.29€, bundled: 1 - Oldschool classic, loved playing those many years ago
• Developer Alliance Bundle -95%, 0.74€, 4 games ranging from 83% to 92% positive reviews, NOT BUNDLED BEFORE - most were bundled before, but it's a good deal if you don't have any of those
• Dungeon Siege Collection -75%, 4.99€, 4 games ranging from 63% to 83% positive reviews, NOT BUNDLED BEFORE - The first 2 parts are gold, not sure about the third one.
• Frederic Bundle -85%, 1.49€, 2 games ranging from 85% to 86% positive reviews, bundled: 2
• Hexcells Complete -70%, 2.69€, 3 games ranging from 96% to 98% positive reviews, NOT BUNDLED BEFORE - "Best casual puzzle game on Steam and Infinite has randomly generated levels. As a result, I've played Infinite for 82 hours." Desidiosus
• Left 4 Dead Bundle -80%, 4.19€, 2 games ranging from 95% to 97% positive reviews, NOT BUNDLED BEFORE
• Penny Arcade's On the Rain-Slick Precipice of Darkness 3 and 4 Bundle -94%, 0.47€, 2 games 83%/86% positive reviews, NOT BUNDLED BEFORE
• Spiderweb Software Complete Pack -70%, 12.59€, 13 games ranging from 75% to 95% positive reviews, NOT BUNDLED BEFORE - "... a must for turn-based & story rich RPG fans.
  70% off, $15 for 13 games, each of them giving 60+ hours of quality play time." XYU Soma
• Two Tribes Classics Pack -85%, 1.49€, 3 games ranging from 89% to 92% positive reviews, NOT BUNDLED BEFORE
• Two Tribes Pack -85%, 2.09€, 4 games ranging from 80% to 92% positive reviews, NOT BUNDLED BEFORE
• Unreal Deal Pack -75%, 9.99€, 5 games ranging from 75% to 98% positive reviews, NOT BUNDLED BEFORE - Just some classics on a lowest recorded price.

Giveaways section:

• Banished lvl 3+
• Cities in Motion 2 lvl 2+
• Company of Heroes lvl 2+
• Outland lvl 2+
• Psychonauts lvl 3+
• Rayman: Origins whitelist only
• Transistor whitelist only

Post your findings below. I will try to update the thread at least twice a day until the sale is over.

And thank you everyone for bumps and the words of appreciation, they're most welcome :)