Bamboo and vampire get big. Like 6-inches. But you need a decent sized mature tank for bamboos, not sure about vampire.
But if you get amano or cherrys or the other dwarf shrimp they get over an inch which is plenty big for me. You just gotta look for the older ones.
I have small ghost shrimp (.5 an inch) in my 10 gallon and when i siphon out the water i rubberband fine netting over the open end so they dont get sucked in.