This is what I carry:

-a small 15mm wrench for my axle nuts
- 2 plastic tire levers
- 1 heavy duty metal tire lever
- chain tool
- a short piece of chain about 6 inches long
- few quick links
- mini bike tool
- 2 spare tubes
- mini pump
- few chain ring bolts
- a small chain ring wrench
- Leatherman Super Tool multi tool