Help me pickup a specific kind of games from my library

You can try LYNE. Not in you inventory but it's quite cheap.

Bejeweled 3
FaeVerse Alchemy
Strata
Faerie Solitaire
& maybe the Zup! games

I'd say Refunct.
PROS:
1) You can play without a sound all the time.
2) A no-brainer game, no actual story, just relaxing views and some jumping.
3) You can leave it for an hour and nothing will happen, you cannot die, you won't be attacked by anything etc.

CONS:
1) It's rather short game (you can finish it in ~30 minutes).
2) I don't know if you can switch to a windowed mode.

Looking through what you and haven't played
Epic Battle Fantasy 4
Legend of Grimlock 2
Evoland 2

One that I would recommend more so with the amount of hours you have in Gemcraft (good game btw)
Bloons TD 5 (I know it's not below 5 but still, it's worth it)

I'd recommend trying this http://www.lorenzostanco.com/lab/steam/u/avantyr
With your library and some filters.

Mini Metro is not too much brain challenging? Really?

Anyway, what about Obulis? Or League of Mermaids? (bit more than $5 though)

I'd start looking into board games.
HOARD, Fox&Flock, Warlock(4x)

Alternative something with turn based combat like Chroma Squad

Something like Darkest Dungeon or Ticket to Ride would be great but didn't see them in your library

1. Go there: http://www.lorenzostanco.com/lab/steam/
   Type your Steam link for it to load your library.
2. Choose "Fast-paced" or "Tower Defense" on filter list. Scroll down to see the result.
   You also can try some Clicker games, they're mostly free on Steam, you don't even need to use a neuron when playing these. They were born for people do multi-tasking but still want to play something.

Steam:

• Golden Krone Hotel
• Yankai's Triangle
• Earthtongue

Free games:

• Cataclysm: Dark Days Ahead
• Infra Arcana
• Soda Dungeon
• deeeep.io/

Btw, I LOVE HyperRogue, I play it all the time, it's the only game I have on my phone. That's cool, I've never seen anyone else mention it before. If you like that then you may like my suggestions: rogue games with a twist.

Zenge
any hexcells game

Card Hunter is free, and I'm still playing it after about 3 years now (between co-op and the randomized dungeon, there's a lot to come back to, even if you're not at all into PvP elements). Even if it doesn't catch your interest for that long, just a single run through of the campaign should take you a couple of days, so it should help serve you as a good distraction. It's a deck-building tactical RPG with emphasis on positioning. Non-pvp elements don't ever time out, so you can completely take your time playing the matches in between other activities.

http://store.steampowered.com/app/545590/Button_Tales/
http://store.steampowered.com/app/495780/Hexoscope/

Both can be picked up for a few cents on DailyIndieGame; one from the store, one from the key trading section.

The binding of isaac
Dungeons of dredmor
Creeper world 3
These are my main ones, although Isaac might have a bit to much action for your purposes. Creeper world 3 I would highly recommend if you like tower defense (with a twist).

pickaga.me usually works when I can't decide what to play. Also, have you tried Kami?

use this:
http://www.lorenzostanco.com/lab/steam/

Papers, Please

Though to recommend you games, as you played (or idled) most games for some few hours.

Just took a look at the lower half of your library. But I don't know most of the games there so I can't help you with that. But as for cheap games which may fit the bill:

• Everyday Genius: SquareLogic - Although I'm not sure if it can be played in window mode but the rest should fit
• One Way Heroics - Fits the three, the fourth too (it is action orientated but it is a kinda turn based) but it is not necessarily easy to learn ......

Well'
Alice Madness returns
Contrast
Castle of Illusion
All Lego games seems suitable for this.

Assuming you're not limited to Steam, here are a couple of non-Steam games. :3

Princess Nom Nom is free and kinda mindless. Nothing bad will happen if you decide to leave it running. Though it could just be a 20-minute game if you're active with it.

Flow Free can last you a lot of hours for free, and then you can choose to buy some more packs to keep playing a bit more. There may the occasional difficult one that needs some brainpower to solve, but I've found that's few and far in between; most of it is easy.

Isaac

Hmm... Portal fits IMO, of course you'll lose some of the plot, but it's still good puzzle game, works without sound, nothing rushes you, and you can stop anytime, without dying etc.

Of course Pixel Puzzle and all of this kind of games, but it depends how much do you like that kind of stuff

Limbo allows player to take his time and plot is basically without words, so it wouldn't require much attention to that

I played Stardew Valley when watching some of TV series, because it requires sometimes much grinding without much attention

X-Com is turn-based tactical shooter, so it doesnt necessarily needs fast reaction and you can stop anytim

But out of my experience I would really recommend to play with watching movies or tv series or anything games like Gwent or Hearhstone, if you consider these as casual games without worrying about rankings it's just perfect to keep your hands busy :)

I hope it will help