Wavedashing was in Tekken before SSB (not to sound mean… just FYI ^^;)
Heihachi, Jin, and Kazuya have a crouch dash f,N,d,df. Canceling these into eachother is wave dashing.
But other characters have their own variations.
Paul and Nina can qcb_qcf~u_d to box step.
Backdash~ss is abusable with everyone in TTT and T5.
Hwoarang has fox step… BT RFF (looks like LFF) 3+4~bb, uf_ub, 3+4~bb (actual input is insane however: I use LFF b,b+3+4, 1+2~4 (the 4 doesn’t register a move, but you need to hold it from here on out) BT 3+4~bb_ff (the direction you travel will be reversed, if you hold the ff or bb input you can cancel into the other foot forward while backturned instead of using uf_ub. Each one looks cool-one is like skipping and the other has wacky jerky legs–not crazy legs however)
Crazy legs involves 3+4~SS which can be done with f,f+3+4~SS or b,b+3+4~SS (in T4 SS right seemed to work best when just doing 3+4 without the dash)
Hwoarang also has snake dash which is a variation on wavedashing. Instead of canceling his crouch-dash into itself he cancels it into a sidestep then back into the crouch dash f,N,d,df~u~f,N,d,df~u (in T4 you could only SS up, no matter what side you were on can’t remember if this changes in T5–but hwoarang also can wavedash normally in T5)
Lei has a multitude of Haha steps and Hoho steps and other crazy stuff that changes each game.
T4 had shadow stepping: BT d,db,d,db,d,db. It was a cool glitch that was pretty useful. I still find myself trying to do it out of habit in T5.
Like I mentioned earlier… Baek and Hwoarang have multi-side step.
SSR~f+3~SSR (people would joke that 2p was stronger that 1p hwoarang in t4 because he could snake dash into tripleSS in one direction)
SSR~b+3~SSR with Baek who also has df++4~f~df++4~f… which is his wavedash. Like Hwoarang, mixing special movements together with Baek is quite stylish.