Game Engines:

Unity

Godot

Software:

Blender (3D modelling + animation)

Trenchbroom (Level Creation Tool)

GIMP (Image editing software)

Krita (Digital Art creation software)

Aseprite (Sprite creation tool)

Languages:

C#

gdscript

gdshader

python

HTML

CSS

JavaScript

Tools:

github (mostly for version control)