I've been on A LOT of game jams and believe me. It's not so hard to make if you have these handy tools~
For the universal tools, we have Aviary:

- It's a full suite of tools solely made for Game Jams. It has pretty much everything you need.
- Image Editor
- Color Editor
- Effects Editor
- Vector Editor
- Audio Editor
- Music Creator
Bad news is... It's gonna be taken down soon so you better download those *.swf files if you need it.
GraphicsNow for the basic tools. Graphics are made from scratch, it cannot be generated (mostly anyways). There are tools to make it easier though.



Sound EffectsAhh yes... Sound Effects. Want something 8-bit? Generated? Well. We have some sound effect generators here:

MusicBackground Music? You need to make them again... Yourself. So have some editors~




Okay, maybe your somewhat lazy to make your music. We got some a bit decent generator for you:
http://tones.wolfram.com/generate/
Well, these will do for now. If you got some questions then tell me.