Let's start with the big one: originally TM was going to be a scratch game called BOTP (Battle Of The Protos) and even BEFORE that it was gonna use the Original TF2 Mercs in the Piemations art style and it was gonna be called TF2D.

Below you can see the original designs for the classes:

Most full names were different but I can't remember any of them sadly, but I can confirm that the Inventor used to be a boy called Norven. (the old names sucked anyways) And instead of PRPL team (which was originally just PRP), there was GRY team.

Alright, now that thats done, time for the smaller stuff:

-The primary for the Explorer was originally called the Hexshot and it looked like this:

-The melee for the Bomber was originally gonna be a soda Bottle instead of the Broken Golf Club:

-The melee for the Incendiary was gonna be a Fire Extinguisher instead of the Fire Axe:

-The primary for the Doctor went through many names, Needle Gun, then Tech-Rifle, then finally Syringe-MG, here's the original design:

-Finally the primary for the Espionage was originally gonna be a Silenced Pistol instead of a Revolver: