I thought I'd already posted something like this, but I can't find it anywhere hehe. Post here with any ESO add-ons that you use, with a brief description and where to find them.
AUI (Advanced UI) - www.esoui.com
This is a UI mod, which give you an extended ability bar, so you can see what potions you have equipped in your quickslots and assign hot keys to them (I use F1-F5). It also has a mini-map included, and a DPS meter. It can show you active buffs and debuffs on yourself and on your target, and shows alot more info on the screen when in combat, such as damage and healing done.
Skyshards - www.esoui.com
Updates the main map and the mini-map with all Skyshard locations. When you collect the skyshard, it removes them from the map so you can easilly see what you still need to collect.
Lorebooks - www.esoui.com
Same as Skyshards, but for Lorebooks. These are the blue glowey ones that give mage guild skill increases.
Harvens All Experiance Bars - www.esoui.com
Allows you to have any of the individual class or skill experience bars active on screen. Useful if you are a level-junkie or want to track a certain skill.