Tools
Always good to have a list of stuff. An ever-expanding, mostly useful list of stuff. Stuff that I use either on a day-to-day basis, or once in a blue moon.
Graphics Stuff
Always find someone better than you to pick your colours.
A great, free online (and offline) pixel art editor and animation package.
I try so many different graphics applications to (badly) create things, and this is the one I always seem to go back to.
Dev Stuff
Obviously.
Really useful if you ever have to manipulate a load of data.
A lua based 2D game framework. Great fun.
Other Stuff
Everyone should have one.
Static site generator used to make this site. Actually really impressed with it.