Useful

Adds a mod menu to view the list of mods you have installed.

Shows information about what you are looking at. (Hwyla/Waila fork for Minecraft 1.16+)

A working voice chat in Minecraft!

Adds dynamic lights to Minecraft as the most feature-complete and optimized dynamic lighting mod.

A featureful and accessible item and recipe viewer

Vanilla+ additions: Jars, signposts, faucets, weather vanes spring launchers, sconces, planters, lights, decoration and automation

Take insanely large screenshots because why not

Open a LAN server to anyone, anywhere, anytime.

spark is a performance profiler for Minecraft clients, servers and proxies.

Lets you see if players are typing, in a GUI, idle, with cool ingame visuals

A vanilla and add-on friendly, open-source mod that adds in more tiers of Netherite!

Fusion allows resource packs to use additional texture and model types such as connected textures!

Help your friends back up after they die (if you can make it in time)

Allows players to temporarily mark locations and entities

Xaero WorldMap / Minimap Extra Features

Changes the default server compatibility check to compare modpack versions

A proximity voice chat mod with audio positioning and lots of features

Never lose your items again!

Spyglass Improvements is a mod that add various functionality and improvements to the vanilla minecraft spyglass.

Adds a trash slot to the inventory screen that allows deletion of unwanted items.

Expertly edit your books with rich formatting options, page utilities and more! And it's all client-side!

A permissions plugin/mod for Minecraft servers.

Brings the sanity mechanic from Don't Starve into Minecraft

Adds a fitting and difficult temperature system to Minecraft, plus more!

A modern take on thirst, compatible with Create, Farmer's Delight & more.

Remove that delay when blocking

This little mod allows you to directly equip your Curios items to the respective slots

A vanilla-friendly mini-map/world-map mod using vanilla Maps!

Take high-quality screenshots on Forge

Via Romana introduces a fast travel system where players can link signs over paths, allowing for instant teleportation between them.

Add bubbles above players heads when they send a message in the chat.

WorldTools is a powerful Minecraft mod that allows you to capture and save high-detail snapshots of server worlds locally.

A mod which substantially improves Minecraft's data driven world generation error detection, reporting, and recovery mechanisms.

A client-side mod that logs exceptions that stop you from joining a server

Overhauls the game's 14 year old text formatting syntax.