I mainly just sell extra keys that I get, Either from humble bundle, or from friends or etc. I don't sell many items but they are all legitimate.
Selling Summary
Battlestar Galactica Deadlock
Age of Wonders: Planetfall
Naruto to Boruto: Shinobi Striker
Just Cause 4: Complete Edition
Pathfinder: Wrath of the Righteous
Jurassic World Evolution 2
Edge of Eternity
Aliens: Fireteam Elite
Life is Strange 2: Complete Season
Bendy and the Dark Revival
Chivalry 2