Custom rooms that implement free-for-all shooters (also known as PvP shooters) have become popular in Rec Room since it is possible to respawn players with Respawn Points. Probably the first room of this kind that gained wide popularity is ^Wastelands by Coal. Nowadays, a simple PvP shooter only requires Respawn Points and a Game Rules chip.
Many free-for-all shooters use the room tag #pvp; you can find these rooms by searching for "#pvp" on rec.net.
Examples from 2019Q2 include: ^AlienProject, ^InfectedSpillway, ^ControlPoint, ^HIDEANDSCREEAM, ^breaking_point, ^Badlands2, ^AfterMath, ^HexagonHeat, ^FlashLightPvP, ^TudorTown, ^SpleefMasters, ^ManHuntPVP, ^AttackOnMothershipBETA, ^LTLeague, ^RecDomination, etc.