What Works With Vanilla

Some mods I have found that have full or partial functionality with Vanilla servers. 

-JEI so you can look up recipes without the wiki. (You will see this to the right of your inventory. Click things to see how they are made!)
-A Minimap (Press J for big map or options)
-Health bars on mobs.
-Some fancy inventory stuff.
-Removal of pop-up notifications.
-Slot checker to see what items can go into things (Left Alt while moused over a slot)
-An overlay to show where mobs can spawn (F7)