Visual Novel recommendations

https://store.steampowered.com/app/615530/Love_Money_RocknRoll/ - i can't recommend this one enough

and if you don't mind NSFW i would suggest
https://store.steampowered.com/app/1582890/My_Catgirl_Maid_Thinks_She_Runs_the_Place/

Chaos;Head is a solid choice, I would've recomennded it otherwise.
For good mystery plots, I'd recommend Never7, Ever17 and Remember11 too.
For a lighter plot, I am kinda uncertain as I also like heavy stuff storywise.

But I may recommend Shan Gui for a short, heart-warming little kinetic novel. In part because I took part in the hungarian fan translation of that VN. (Edit: to my knowledge its also officially part of the Definitive Edition)
Its a rather easy read and its not expensive either.

I sometimes read visual novels :D So for now I can recommend:
Ballads at Midnight and Solstice.
Sadly Solstice is not on sale :( Maybe in other stores.

Didn't see Steins;Gate on your list.

https://store.steampowered.com/app/303310/The_House_in_Fata_Morgana/

https://store.steampowered.com/app/1230140/ATRI_My_Dear_Moments/

https://store.steampowered.com/bundle/2710/STEINSGATE_SERIES_BUNDLE/ anime did it better for me though.

https://store.steampowered.com/app/324160/CLANNAD I mean how can you not...

https://store.steampowered.com/app/1506980/Lay_a_Beauty_to_Rest_The_Darkness_Peach_Blossom_Spring

https://store.steampowered.com/app/939400/LoveChoice/

https://store.steampowered.com/bundle/1975/Story_of_Eroolia_Collection/

https://store.steampowered.com/app/1528130/Suicide_Countdown_7_Days/ few hours with enjoyment

https://store.steampowered.com/app/687260/Tokyo_Dark/

https://store.steampowered.com/bundle/9605/Grisaia_Collection/

https://store.steampowered.com/app/716340/Blackberry_Honey

https://store.steampowered.com/app/1714320/Find_Love_or_Die_Trying/

https://store.steampowered.com/app/891510/Loves_Sweet_Garnish/ just cute girls doing cute things.

https://store.steampowered.com/app/251990/Long_Live_The_Queen/

https://store.steampowered.com/app/549860/One_Night_Stand/

https://store.steampowered.com/app/522880/PSYCHOPASS_Mandatory_Happiness/ just because I'm a fan of the anime

https://store.steampowered.com/app/1571910/Dear_Althea/ few bugs but it's ok.

https://store.steampowered.com/app/1202540/Marco__The_Galaxy_Dragon/

https://store.steampowered.com/bundle/11706/MuvLuv_MEGAVERSE/

https://store.steampowered.com/app/1578860/Billionaire_Lovers/ pretty cheap, i think it's worth even without the discount. Although it's sale rn.

https://store.steampowered.com/app/635940/Little_Busters_English_Edition i love both the anime and the vn

https://store.steampowered.com/app/1591490/Distant_Memorao/

https://store.steampowered.com/app/1769320/Athanasy depends on the mood.

https://store.steampowered.com/app/1044490/The_Expression_Amrilato

https://store.steampowered.com/bundle/18378/Senren_BankaRiddle_Joker_Set/ (except for Senren Banka, PARQUET is the best here for me)

https://store.steampowered.com/app/1044620/Aokana__Four_Rhythms_Across_the_Blueanime was meh but vn is great.

https://store.steampowered.com/app/1418180/MUSICUS

About some that aren't on your list I can recommend:

• milk inside a bag of milk inside a bag of milk (really short/psychological horror)
• milk outside a bag of milk outside a bag of milk (short/psychological horror)
• Sound of Drop - fall into poison - (horror)
• Ame no Marginal (mystery/atmospheric)

Also I really love VN's with grid dungeon gameplay, there is a few that I know of that are interesting:

• The Silver Case (mystery/investigation)
• Death Mark (horror)

For lightheaded stuff:

• Bard Harder ! (short/TTRPG theme)
• Monster Loves You (short but there is like 20 endings ?)

Anyway I hope you will find something you will enjoy to read !
Your list have a lot of interesting stuff so I might steal it, for science of course :3 (I really need some more good vn's myself)

If you like coffee talk, i just want to point out that there is this https://store.steampowered.com/app/1663220/Coffee_Talk_Episode_2_Hibiscus__Butterfly/

https://store.steampowered.com/app/1084640/Chicken_Police__Paint_it_RED/ is also nice, although it isnt horror mystery genre (and im speaking this from someone who like mystery genre as well)

Since you havent played danganronpa v3, you might want to give it a try.

And then steins gate is nice. I havent played the game, but i watched the anime.

Chaos;Head and Steins;Gate are up there, for sure. (For C;H, you might want to look into fixes if you want the NOAH release.)

I also don't see Corpse Party: Sweet Sachiko's Hysteric Birthday Bash or Corpse Party: Blood Drive on your list. I've yet to play them myself, but I want to say it should be a safe bet they're as good as the previous two. (Hesitant to say the same about Dead Patient, though, as it never really reached a conclusion.)

And since I feel safe recommending these, Amnesia: Memories and Hakuoki: Kyoto Winds/Edo Blossoms are two solid otome games bound to keep you busy for a while.

I love Visual Novels. Here are some suggestions I've played.

The Sekimeiya : Spun Glass is a really long complex mystery story.
https://store.steampowered.com/app/1432500/The_Sekimeiya_Spun_Glass/

I didn't see Zero Time Dilemma on your list, but that might be because it plays more like an adventure game than a VN.
https://store.steampowered.com/app/311240/Zero_Escape_Zero_Time_Dilemma/

But if you like Kotaro Uchikoshi's work (zero escape series), then I recommend Ever 17: The Out of Infinity. Which is also a mystery story.

Yeah,Umineko would be a nice addition.

I recommend:
DATE A LIVE: Rio Reincarnation
PixelFade VNs
Cross Princess
Senren＊Banka
食用系少女 Food Girls

Well we talked before when you did the whole sakura month for play a win event so you know I had to pick up some visual novels as always

Had to complete the set to sakura so succubus 7, gym and that leveling up girls game
Every Summer Holiday and Rapscallions On Deck to complete the chanimk set
Astronomic Date which as you put above would not be your thing but I own all their other games so I thought I may as well buy it
A TAVERN FOR TEA and a pet shop after dark to well complete another set. a pet shop seems more point and click but tavern for tea sounds like coffee talk but tea
Got Max's Big Bust 1 and 2 in a bundle

Once I get a bit more money you can guess it more visual novels to complete lists probably like heart in the woods

I also brought AI: THE SOMNIUM FILES - nirvanA Initiative. I see you played it in your vndb account. How did you find it?

AI: The Somnium Files

and my nostalgia bone will not let a question about visual novels pass without mentioning Ace Attorney

Ok, so here we go:

• Zero Escape (specially if you liked AI:TSF)
• One Thousand Lies: It's free! It's short! It's an absolute ride that made me cry like a baby!

I probably can come up with more if I think for a bit. Meanwhile, I need to ask: is the coronel sanders vn any good? I did download it as a joke, now I'm genuinely intrigued.

I absolutely recommend GNOSIA for a very different type of visual novel based around the party game Werewolf/Mafia. It's short for a VN but well worth the time!

https://store.steampowered.com/app/1126320/Being_a_DIK__Season_1/

highly recommended

Kindred Spirits on the Roof, Highway Blossoms and Blackberry Honey if you're into yuri.

Not much of a horror person myself unfortunately, and it looks like whichever few I had in mind are already on your list. I'll just leave my own here in case there's anything you may enjoy in another genre (order by my Vote score and filter however you like). Nice to see a fellow VNDB user!

If we take away the cyberpunk setting and dinosaur characters, that would seem like a lovely down-to-earth novel about problems, that are familiar to us and that we experience on a monthly basis.

https://store.steampowered.com/app/1596730/Dynopunk

Only "pure" VN I've played is Root Double. It definitely falls into the mystery+horror theme you're looking for. I guess I'd recommend it to you. (I mean, I liked it by the end, but I'm definitely not a VN person and, to me, it felt like it dragged on at times, but the fact that I finished it at all means it was good, right? ^_^' )

Vampires' Melody is really good, and also very cheap too! I really liked it.

RB: Axolotl is really different, and I fully enjoyed my time with it (and not just because it's about axolotls, although I'll admit that was a big part of why I bought it). Despite the initially cartoonish presentation and healthy dose of humor, this really does fit firmly in the mystery/psychological/horror spectrum of VNs. Maybe not quite as intense as some of what's on your list, but it definitely gets darker and heavier than you might expect, with some decent twists along the way. Well worth a look if you are after something different.

Here is a less-known but good one: Guilty Parade

Mystery and horror:
https://store.steampowered.com/app/2097750/AOISHIRO_HD_REMASTER/

I played it in the past with a fan translation. It can be a little bit frustrating, since it has over 60 endings if I remember correctly - and mostly Bad Endings. But the true ending makes up for it.
The English translation of the Steam version isn't really good according to the reviews, but in the Discussions you can find a link to apply the fan translation from the past, which is better.

Fantasy:
https://vndb.org/v24110 - Meteor World Actor

Good, solid title around crime and fantasy. Also has a sequel already. Most likely there will be a third part as well which isn't announced so far.

Also fantasy:
https://vndb.org/v16337 - Sorcery Jokers

Also very good. And good characters.

Not really mystery or horror, but with
https://store.steampowered.com/app/377670/Gsenjou_no_Maou__The_Devil_on_GString/ you already played one of the best ones in my opinion.

This was my first visual novel/eroge ever and unfortunately I couldn't find any title which had such an emotional impact on me since then. And in combination with the epic soundtrack, it's just a masterpiece.

But I would buy it outside of Steam and buy the original version with the English patch or wait for the 4:3 official version, since the widescreen version on Steam has cropped images which is a little bit disappointing.

I can recommend much more, but none of them are mystery/horror, since it's not my genre. With already over 200 visual novels (but mainly eroge, so 18+) played, official English versions and also fan translations, I can say it's my favourite genre in general :)
I also translated a few of them to German already - the last one being https://vndb.org/v7738 (Kimi to Kanojo to Kanojo no Koi). I would say this one is also mystery. If you played Doki Doki Literature Club (of which I translated the original one), I think you'll also like this one, since it's somehow similar.
Anyway, most of the ones I played aren't on Steam.

Zero Escape: The Nonary Games
Zero Escape: Zero Time Dilemma
428: Shibuya Scramble
STEINS;GATE
CHAOS;HEAD NOAH
CHAOS;CHILD
Spirit Hunter: Death Mark
Spirit Hunter: NG
Raging Loop
GNOSIA