Ideas for a starter gmod addon?

I'm deciding to head back into Garry's Mod, and make some addons to get some more experience with Garry's Mod Lua, using the prior knowledges of Javascript, Python and C#.

What ideas do you have for a basic functioning addon as a starting project with Lua?

u can try to make a hud for the game it's extremely hard to found a good one for free