Who are some good counter junglers/invasion junglers that aren't played often? and is there a difference between the two or are they the same?

Thanks

EDIT: Also any tips on how to be a good jungler/counter jungler as well?
Really like the jungle role and want to be alot better at.

Shameful bump

Udyr, Nocturne, Shyvanna are all great invaders.

Counter jungler and isn't played often: TRUNDLE

Best duelist in the game early to mid. Gives Lee Sin nightmares.

Mundo

stealing big wraight and going to your respective buff is really strong, early game that wraights its the matter of lv3 before the second buff, and that for some junglers means their life and jungle speed

Nunu and Shyvana come to mind. Nunu is great because he can simply take his blue and walk over and constantly steal blue wraith/brown wold and deny early xp

Shyvana is rediculously fast and stays reasonably high health. She messes up slower junglers like Nautilus and such by walking into their camps and stealing camps before they get there

Nunu is good for stealing big wraith, Shyv and Mundo are both very fast, dominant junglers that are fun to play and very good.