Questie is one of the most useful Addons for Classic WoW overall. It shows you the locations of quest givers, quest locations and any other quest related information on the map. Don’t know where to find those ogres you need to kill? Just open the map, and Questie will show you! This is my absolute top pick.
While many people prefer Auctioneer, I like Auctionator a lot. It let’s you easily check the prices of one or multiple items on one page, without a lot of scrolling. You can buy several stacks at once without hassle, and it makes selling a lot easier, too. Basically, it’s a light-weight version of Auctioneer with some extra utility. Very useful for Auctionhouse trading to make gold!
3. Postal (?)
If you sell a lot on the Auction House, or just get a lot of mail in general, this small Addon is for you. With the click of a button, you can empty your whole mailbox. Never click 50 mailed items individually again! An absolute must have in terms of Addons for classic in my opinion.
Grid provides unit frames for raids in a compact, simple way that doesn’t clutter your whole screen. It is very useful to keep an overview of how the raid is looking during boss fights, with one quick glance at it. This Addon is very popular with healers, especially in combination with the next one in the list:
Clique basically does what it says on the tin: It let’s you configure modifiers for you mouse buttons, and bind spells to them. So, for example, you can bind your Healing spell to Shift+Left Click. With this setup, you can just shift click on the unit frame of a party member to cast the spell. This is very useful, especially in dungeon or raid scenarios.
Boss Mods are a must have for any raider. Deadly Boss Mods provides timers and alarms for important boss abilities. This gives you time to react when you need to avoid something or taunt the boss. Many people also use BigWigs for this, and I recommend installing both of them, if you are unsure which one your guild is using.
Have you ever been lost in a massive dungeon, like Maraudon or Blackrock Depths? Or have you wondered what kind of loot you might get in a dungeon or raid? Well, with Atlas and AtlasLoot combines, these problems are no more! It has maps of all the dungeons and raids, and loot tables for every boss, including trash drops and rare mobs within dungeons.
8. Cartographer (?)
This one might not be for everyone. Classic WoW is about exploration and adventure, and having and Addon that reveals the complete map might not be what you want. But if you have played through the game several times and just want to see the whole map, Cartographer does exactly that. It also adds coordinates and some other utilities.
9. Quartz – Classic Addon
This simple Addon adds a configurable castbar. You can move it, resize it anything you want. It had tons of useful options! Have you ever wondered how long it takes to craft a lot of items at once? Quartz shows you how long it will take when you click on “Craft All”. Very useful, even if you are not a caster.
10. Prat for Classic
Everyone needs a chat addon. Prat adds class colors to the chat box, time stamps, and tons more usefulness to your chat if Classic WoW. There is also a good alternative for this, Chatter, which has similar options. I can’t live without a chat addon anymore, and so it had to make this list of Addons for Classic.
EDIT: Updated the links. I will keep them updated as the Addons are ported to Classic. The ones that are not 100% working have a (?) next to them.