neoforge optimization mods - 1.21.1 (additional)

Clumps XP orbs together to reduce lag

Optimization mod that focuses on things other than rendering

An efficient and non-locational redstone dust implementation

Completely removes recipe book from the game, optimizing player data.

Attempts to optimize the generation of Jigsaw Structures and NBT pieces

Async particle tick/rendering

Greatly improve your fps with virtually no side-effects on graphics quality

Improve your Create FPS when shaderpack is on, up to 50%

Instanced rendering for entities and block entities using Flywheel

Advancements optimization mod, updated fork of Icterine with added features

A lightweight entity-tick-scheduler for doubling your TPS.

Provides powerful network optimization capabilities for all mainstream systems.

Off-thread event polling for improved performance

Distribute HUD updates over multiple frames to improve performance

EXPERIMENTAL: Highly unstable alternative world format for Minecraft. Here be dragons.