Rebirth

Rebirth is an end-game function that allows players to delete everything that they've worked for except their gamepasses and pets for a boost in their gem multiplier. All players start off with a gem multiplier of 1.0x (No multiplier) when they first started playing. The multiplier will go up when you rebirth. The more you rebirth, the more multiplier you'll get.

Here's a list about rebirthing.