I found some Tekken screenpacks on the web, here are the links :
Tekken 3 : http://mugenguild.com/forum/topics/tekken-3-mugen-screenpack-85098.0.html
Tekken Tag Tournament/Tekken 3 (Lots of Bugs) : http://www.angelfire.com/games4/mugenla/maindl.htm
Tekken 3 (Not the same as the first one) : http://m.youtube.com/#/watch?v=m_G4oz8LgPg (Links are in description)