Games

Classics like The Incredible Machine and Ultima 8 come to mind.

Rimworld can be played only with a mouse pretty good. And City Skylines too

Backpack Battles! Fantastic little inventory management game with a load of replay value.

If you don't mind something older, both Star Wars Knights of The Old Republic games can be played only with mouse. It's bit clunkier than also using a keyboard, but doable. I used to play them like that while smoking many years ago.

Cookie Clicker

Age of Empires, XCOM, Cities: Skylines, Divinity Original Sin 2, Starcraft, +1 for OSRS.

Peggle Deluxe and Peggle Nights are awesome mouse-only (except typing name i think) casual games!

https://store.steampowered.com/bundle/15495/Peggle_Pack/

If you want an alternative to Slay the Spire i can recommend Monster Train; you mainly summon different Hellspawn and cast spells, which gives it more of an Magic the Gathering feel.

If you want an ARPG fix and have thumb buttons on your mouse you can try Chronicon, don't let the gfx stop you, it's an excellent hack&slash game, and you can put all your skills onto 1 button if you like - i use the middle and the right button for most builds and thumb keys for pots

If you want a new spin on Darkest Dungeon, give Iratus - Lord of the Dead a try. Or if you played a lot of Darkest Dungeon and want more of it, try Black Reliquary, a huge (and free!) mod with a lot of new mechanics!

Going into the same direction as Into the Breach is Shotgun King - the final Checkmate. It's really fun and the higher difficulties really make your brains work out. Workshop support with lots of extra content included! Also great for Turn-based Tactics is Invisible Inc., putting you in control of an spy agency which has been hit hard and tries to recover.

For arcade games i can recommend Utopia must fall - it really captures the spirit of old arcade games, but feels real fresh. You can also go for Nova Drift, which is also an excellent arcade game.

Then there is Cultist Simulator and its spiritual successor, Book of Hours. It's basically a card based riddle game, and very atmospheric.

There is always Shattered Pixel Dungeon - it is also available on Steam or Gog, but you can download and play it for free from the link i provided.

I think your collarbone might have healed until you've finished that list, have fun!

Warcraft? Sid Meier's civilization?

Or in general any top down RPG game, like RuneScape.

I'd say most RTS games I can think of can be played with just a mouse

Older diablo-like ARPGs didn't really rely on the keyboard too much IIRC, the modern ones do tend to rely on the keyboard a bit more

If you don't mind older games, basically the whole genre of point and click adventures is this by definition

Uow about some visual novel style games like 999, Hotel Dusk (DS emulator), Ghost Trick, Professor Layton (DS emulator or mobile)

Since Ellipsis hasn't been mentioned yet, here's my recommendation:

Ellipsis is an action-packed Avoid ’Em Up with minimalistic, yet powerful neon styled visuals. Guide your ship through a mysterious universe while deftly avoiding hordes of roaming enemies, spikes, lasers and more.

Ellipsis on Steam Store

kentucky route zero

Peggle, Nubby's Number Factory, Peglin, Ballionaire

Nubby's Number Factory

Give Kingdom of Loathing a try.

Get a giant D-pad for one of your feet to use for wasd

I installed PPSSPP on my phone and paired a switch joycon. Played through a few really good games that way when my kid required being held to sleep. I'd imagine you could pair one to your computer and find some games that you'd like.

A large proportion of games that have both mobile and PC releases are going to be designed around mouse-only use.