lexaloffle.com/pico-8.php
And also TIC 80:
tic.computer
And LIKO-12:
liko-12.github.io/#/
These are purposefully limited to simplify game dev with an old school feel.
lua.org
It's also one of the few open source projects that does zero propaganda style promotion.
love2d.org
This is for doing 2d style games like platformers, dungeon crawlers, and anything pixel based, rather than model based. It's open source and runs on a *ton* of platforms. Again, it also uses Lua but Lua is a great language.
love2d.org/wiki/love.phys…
Graphics:
love2d.org/wiki/love.grap…
and Audio:
love2d.org/wiki/love.audio
godotengine.org
Godot is able to use multiple programming languages, 3D and 2D, pixels or rendered, and has a dev environment.
Docs are pretty good:
docs.godotengine.org/en/3.1/
Next you need something to make art and Krita is free:
krita.org/en/
aseprite.org
and
piskelapp.com
My main problem with all pixel editors is they make me click too much.
All free:
opengameart.org
Itch.io is a great community too:
itch.io/game-assets/fr…
High quality:
craftpix.net/categorys/tile…
audacityteam.org
If you're into trackers:
openmpt.org
And most MIDI composers are garbage. No idea why midi is so bad.