Attachment
Anna Williams' ending shows her and her sister Nina on the beach sunbathing, when 3 men try to impress them. In the Japanese release, Nina gets jealous of Anna as she revels in the attention, so she unclips Anna's bikini top and walks away with a smile. In the international release, this scene was changed to have Anna simply walk away with the men while Nina is left on her own sunbathing.
Contributed by ProtoSnake
Attachment
In Paul and Bryan's stage is a piece of graffiti that says "Soul Edge". This is a reference to another Namco game, Soul Blade, which was titled "Soul Edge" in Japan.
Contributed by DeerBoarDude
Harada, the producer of Tekken, originally designed "Tekken Ball" as a simulator to help people practice air juggles. Initially, a player had to hit the ball and juggle it to a basket, somewhat similar to basketball. However, Harada found the original version of "Tekken Ball" to be frustrating and decided to make it a competitive game.
Tekken 3 has a guest character in the form of Gon, a silent little dinosaur originating from a manga of the same name. His secondary costume, where he wears a turtle shell, references a time when he did so in his manga, as well as the fact that his mother was a turtle.
Contributed by Psychospacecow
If you play as either Jin or Xiaoyu 50 times, they will be wearing a school uniform. If both of them are wearing the uniform when chosen, the fight will take place on a school stage called "Mishima High School".
Contributed by Ghost
In the arcade cabinet's data, there are references to a secret character named "SAKE", though it is simply Yoshimitsu's model using Jin's move set.

Katsuhiro Harada has gone on to say that SAKE was originally planned for the game as an additional animal character, however SAKE was actually a salmon. No matter if the players punched or kicked, the salmon would simply flop around and make a flapping noise. This was removed as they were concerned that players would be angry about spending 100 Yen to play as a fish that can't do anything.

There were also plans for another character named INSECT, who would be a giant praying mantis. This is because there was a bug in the program which would make characters arms, legs and waists appear incredibly skinny, and they looked like a praying mantis. The idea was dropped as there weren't enough resources, what with adding so many other new characters.
Contributed by Dazz