I love to create new stuff for my 1E/OSRIC game.
Recently I was telling my son, one of my Players about how versatile AD&D 1E is an d the ability to make just about anything you want as long as it fits within the system and doesn't break other things in the game.
To make my point, I am creating a new demi-human based on the Klingons from Star Trek. My son and I are making a new demi-god based on Marvel Comic's Beta Ray Bill character. We have already created a new fighter sub-class also based on Marvel Comic's Captain America. In the recent past I have created a new Demon Lord and a Deity.
1E is terrific for creating your own world and everything in it. it's a Homebrewer's delight. At least, that's how I roll.