Gimloader автор TheLazySquid

Gimloader is a Gimkit plugin loader and manager that works within your browser. You can install plugins to customize many things about the game, from the way the camera works to the appearance of your character.

A variety of official plugins can be found at https://gimloader.github.io/plugins, and others can be found online that are created by other developers. Be warned, installing a malicious plugin could compromise your Gimkit account.