BLF blocks direct links to roblox, so search them yourself.
Poliguns - Fun minimun-inspired FPS/TPS shooter, feels like another game.
Whatever Floats Your Boat - Building/PVP build-a-boat and battle. Fun with friends... if you have.
Noah's Doom Engine - DOOM engine recreated in Roblox. You can test weapons, pickups and kill some enemies, high fidelity to original game.
Sound Volblox - Guitar Hero esque with some more buttons - Easy to extreme difficulty available, ryhtym game.
Armored Patrol - Simple but fun combined arms combat game, 7vs7, conquest game mode, no P2W.
Super Bomb Survival - PVP (optional, recommended) Survival game. Fun, very well done. Has power ups and stuff.
ROSES - Horror (not scary, btw) game with excellent graphics for Roblox, has a narrative (wow).
Before The Dawn - Dead by Daylight inspired game. Hero, Slayer and Victims.
Breaking Point - Mystery "Find who is the murderer" / Survival Game.