For Minecraft 1.16.5 - Troxill Client

. Jax didn't want a fight, but he knew Troxill’s "Combat-Link" would give him the upper hand if things turned sour. He slipped into "Invis-Render" mode, making his character model nearly impossible to track against the shifting shadows of the netherrack.

However, there are legitimate uses:

If you are ready to dominate the 1.16.5 scene, Troxill is your key. If you just want to build pretty houses in a warped forest, stick to vanilla. Either way, the Nether waits. Troxill Client for Minecraft 1.16.5