Peaceful Pack mod 1.8, 1.7.10, 1.7.2 include ways to get items you can't usually get in peaceful mode (such as bones and string). There are 4 major parts to the pack, the first 3 (fossils, sulphur and flax) all started as a seperate mod but I decided to converge it all into one pack.

Peaceful Pack mod adds a new way to get all the mob drops in vanilla Minecraft without having to kill any monsters. This is both useful to just get more of those items with monsters, or by just not playing with monsters at all.