Ferrite Core (Reduces the memory usage of Minecraft)

Fabric Skyboxes (Adds the ability for resource packs to change Minecraft's skybox)

Opti GUI (Enables custom GUIs through resource packs)

Continuity (Allows for connected textures through resource packs)

Sodium (FPS BOOOOOOOST!)

Iris Shaders (Adds the ability to run shaders)

Lithium (Improves a number of systems, but for example: AI, physics, block ticking)

More Culling (Culls many different blocks, or in other words makes them disapear when offscreen)

Debugify (Fixes many bugs, some of which could affect performance)

Sodium Extra (Adds more options to sodium)

Modern Fix (Reduces Mincrafts Memory usage and fixes many bugs)

Entity Texture Features (Adds more properties to entities that resource packs can change, for example to make them glow)

Krypton (Improves multiplayer performance)

Nosium (Improves chunk performance)

Faster Random (Speeds up world generating times and also improves your performance when generating chunks)

Concurrent Chunk Management Engine (Improves chunk performance)

Fast Ip Ping (Allows you to ping multiplayer servers faster)

Thread Tweak (Allows you to improve Minecraft's CPU scheduling)

Reese's Sodium Options (Adds more options to sodium)

ImmediatleyFast (Optimizes minecrafts rendering system)

Entity Culling (Culls entities when offscreen)

Bad Optimizations (Optimizes many things outside of rendering, for example the sky color)

Dynamic Fps (Limits Minecrafts fps when you are not on the game, saving computer resources)

Entity Model Features (Allows resource packs to change entities models)

Entity Sound Features (Allows resource packs to change entities sounds)

Sodium Shadowy Path Blocks (Fixes a Sodium side effect that removes the shadows from path blocks)

Very Many Players (Improves minecraft's performance with large playercounts)

Mod Menu (Allows you to see and configure the mods in EfficientMC)