One of the smallest games in terms of disc space is Animal Well with under 40mb.

Stardew Valley works pretty well with a controller

I’d just take a look at the Steam Deck Verified pages as that’ll give you a good idea about a game (at least though Proton).

Vampire Survivor is ~600 Mb. Balatro is ~150 Mb. I will second Brotato.

Nobody has said Hades or Cult of Lamb yet? Uh

Balatro

Drop Duchy

Into the Breach (I think this one works on Linux)

FTL

UFO 50

Crypt of the Necrodancer/Rift of the Necrodancer

Super Motherlode (since it looks like you used to play flash games)

Dave the Diver

Vampire Survivors

Hades 1 (it's still fun even after 2!)

One Step From Eden

Here's my list of currently installed below 10 gigs:

• 20 Minutes Till Dawn - 128 MB
• Katana Zero - 220 MB
• Donut County - 310 MB
• Mini Metro - 325 MB
• Hyperlight Drifter - 510 MB
• Yes, Your Grace - 740 MB
• Motorslice Demo - 960 MB
• Battle Chef - 1.3 GB
• Tunic - 1.7 GB
• SEKTORI - 2.7 GB
• Deaths Door - 3.6 GB
• BallisticNG - 4.5 GB
• Ruiner - 10.61 GB (Just a tad over 10, but such a good game for Deck)

Check out portmaster

Haven’t seen Dead Cells mentioned. Love that game.

• brotato - 2d shooter+deck builder
• mindustry - I recommend this all the time. Open Source, RTS + FactoryBuilder, fantastic game.

Both < 1gb

Dark Souls 8gb Raft 10gb Blasphemous 1 & 2 4gb each TMNT Splintered Fate 5gb it's a weaker Hades, but still pretty fun. Megabonk 500mb Ball x Pit 600mb

I remember I fit binding of isaac and an archlinux install into 10 gigs of storage using btrfs transparent compression.

The computer was a craptop with only 32 gigs of flash storage overall.

These are all smaller games that I've enjoyed playing on my steam deck, none of them are online multiplayer focused though:

Inscryption

Celeste

Crypt of the Necrodancer

Spelunky

Bad North

Carrion

Death's Door

Anything emulated

Guild wars reforged is good. Only 8 skills means you can map 8 or 4x2 buttons easily.

DREDGE

Also Skul the Hero Slayer

Absolum is a nice new roguelite / beat-em-up, played it in local co-op with a friend. Size was around 5 GB.

Pico8 has some fun games.

Been playing through persona 4 golden on my deck, it's about 9 gigs on size off the top of my head

Also dark souls

Silly Poly Beast - 3 GB Another Crab's Treasure - 7.7 GB

Rabbit and Steel - 376 MB, coop PVE game, plays a lot like FFXIV raids

Realized you can significantlly compress ps2 roms using emu decks compression tool, and have saved quite a bit of space doing that, shrunk the size of each rom by more than half

helldivers has a build that is like 30 GB now. runs the same as before on my fedora system.