Question about mods

I’ve been playing DoL for about a year now, but I still feel like I’m barely scratching the surface of how the game works.
I’ve been curious about mods lately, but I have no idea where to start. Are there any "must-have" or recommended mods that you guys enjoy? Also, I’m curious—is it common for most players to use mods, or do most people stick to the vanilla game?
Any advice would be greatly appreciated!