NoFramerateLimit

Minecraft caps the FPS to 60 if not in a world. This leads to everyone with a monitor above 60hz to have a lagging cursor when in fullscreen, which (at least to me) is really annoying.

This just removes that cap, which should cap the fps to either your refreshrate if you use vsync, or your ingame's set limit (or uncap it if it's set to "unlimited")

NOTE: This will basically turn your GPU into a skyrocket, because it's putting out as much fps as it can (for me my GPU is at 85% and gets me 4500fps)
this may not be necessary, and you may want to cap your ingame-fps to smt slightly above your refresh rate.