Some small things that I really can't believe haven't been implemented yet:
- Forestry cocoa been farms, seriously how has this not been added yet. Maybe it's been delayed because of the multiblock farms development I don't know, but as of now it's just a lot of block breakers and deployers that can get very very VERY bulky after a while.
- Xeno's Reliquary, mob blood. I have no idea what it'd be used for but you could get it by killing mobs with a syringe. Just imagine how cool it'd be on SMP, "Hey guys, I have an entire tank full of mob blood, want some?"
- Thaumcraft 3, a watch that controls time. As of now there's not really any use for the tempus aspect and there is not one single mod that adds a (reasonably non-op) way of controlling time. It would take 1000 vis from the environment and cause a ton of flux. But it would totally be worth it!
- GregTech, Thaumonitory Generator. It adds a generator that runs off dragon eggs, why not vis?