Where are those giveaways coming from?

Humble Store @ $0.89

I noticed the same but I haven't found any discounts on ITAD.
Just coincidence?

https://www.steamgifts.com/discussion/lGoWT/humble-bundle-humble-strategy-bundle-2019

Plug In Digital Build-Your-Own-Bundle by Humble Bundle maybe? As that was about 2 months ago.

Friday special #61
or
Nemesis Bundle 4

Bundle Stars Mega Pick & Mix Bundle 3
https://www.steamgifts.com/discussion/RqjEX/bundle-stars-mega-pick-mix-bundle-3-build-your-own-bundle

Some chinese site, equivalent to those shady russian wholesale ones.. 3 cents (if i got those symbols right..)

Also part of the mystery deluxe bundle fanatical is running.

I was wondering about that one too, but they are all from the same user:

i have a lot of these from unsold gaming magazines

Random drop here https://www.steamgifts.com/discussion/TgXYU/fanatical-elite-mystery-bundle

Lootboy.de for 19,999 coins

+1

Looks like dev keys to me.

Humble bundle store around £0.53 for me anyway at least.

Humble Strategy Bundle 2019

I think it's one of the games given randomly from Loot Boy

https://www.steamgifts.com/discussion/e1G1q/fanatical-lore-bundle

Probably this - https://www.steamgifts.com/discussion/M9IyO/indiegala-hump-day-bundle-69

Probably this:
https://www.steamgifts.com/discussion/vKXCi/lootcratechronogg-loot-play-monthly-march-2019-5-incl-exoplanet-first-contact

https://www.steamgifts.com/discussion/I2O37/groupees-build-a-bundle-52-live

https://steamkey.exaccess.com/#!digiseller/detail/2614211

Alienware Arena
https://www.steamgifts.com/discussion/Grznw/breach-steam-early-access-key-giveaway-free

It was part of an old bundle (now expired) and there is really only one giveaway for it up, so most likely an old, spare key from said bundle.

That shady Russian giveaway site.

giveaway su

Humble Bundle Curve Digital... Serial Cleaner is in the first tier.