Sometimes you stumble over a tool or software that just helps so much in development and makes things so much easier. There is so many out there though so it is easy to miss something. Have you guys found some that you just can't see you could live without or that just makes the job much easier?
I think my pick would be Pyxel Edit for making easy tilesets and pixel graphics for games, you can even use it as a level editor and import it to your game directly, adjusting the graphics if you need and building the levels at the same time: http://pyxeledit.com/