WHICH MODIFICATIONS ARE ALLOWED?
In the past we had a specific whitelist of allows modifications, however we no longer do. Any modification is allowed as long as it follows the same principles as the rules. In general, this means that the modification mustn't adversely impact others in the game:
It cannot cause instability or lag for the server.
It cannot cause instability or lag for other players.
It does not prevent others from playing a Vanilla Minecraft game.
XRAY, ESPs and other tools commonly used for hacking, griefing and cheating are not allowed.
This means that modifications like automatic clickers and AFK fishers are allowed.
Recommendations
For those who want to use modifications, but are unsure where to start, we compiled the following list of recommendations. All of these mods require you to install the Fabric Loader. If you are unsure how to do this, a tutorial is provided at the end of this page.
Essentials
Mod Menu - View and configure mods
Sodium - Greatly increase rendering speed
Lithium - Greatly increase tick speed
Starlight - Greatly increase chunk loading speed
Krypton - Increase network speed
Ferrite Core - Decrease RAM usage
Nice to have
Iris - Beautiful shaders, compatible with Optifine shaderpacks [LAG]
Fabrishot - Take screenshots in 4K
Bobby - Increase render distance higher than the server
Plasmo Voice - In-game proximity chat
Resounding - Realistic sound physics, 'shaders' for audio
Libraries
Fabric API - Needed by almost every other mod
Cloth Config - Required by most other mods
Others
We do not recommend the use of Optifine, since it is incompatible with most other modifications. If Sodium and Iris are not sufficient replacements for you, check out this list of Optifine alternatives.
Installation Guide
Installing Fabric and Fabric modifications is relatively straight-forward. If you are still unsure, you can use the following tutorial.