Game Engine

Godot Engine - Free and open source 2D and 3D game engine
Godot provides a huge set of common tools, so you can just focus on making your game without reinventing the wheel.

Art

Aseprite
Animated sprite editor & pixel art tool

Pipeline

Home - Aseprite Wizard
Aseprite Wizard for Godot. Import animations from Aseprite to Godot.

Godot Addons

LimboAI Documentation — LimboAI 1.0 documentation

Audio

Soundly - The Complete Sound Effects Platform
Find your perfect sound in the massive Soundly cloud library, use our powerful search engine on your local files, and Drag&Drop sounds to your favorite tools!
Audacity ® | Free Audio editor, recorder, music making and more!
Audacity is the world’s most popular audio editing and recording app. Edit, mix, and enhance your audio tracks with the power of Audacity. Download now!

https://handbrake.fr/