One settings window for all your mods, right in the game. Any mod that supports UMM gets its own tab with its own settings, and whatever you change stays put after a restart.
Open it with Esc (works on the main menu or in a match). By default it sits in the top-left corner. On its own it does nothing visible; it only shows up once you've got a mod installed that hooks into it.

Mods that support UMM
Sinners and Statues Tracker, made by me: https://gamebanana.com/mods/692472
dacooderr's QOL Lite - a lot of the mods in this collection already support UMM: https://gamebanana.com/mods/678180
More to come.

Making a mod that uses UMM?
Adding your own tab takes one snippet and doesn't tie your mod to UMM, so it works fine whether or not a player has UMM installed. Developer guide: https://xaohs.github.io/universal-mod-manager