Hey guys I'm here to share with you some useful addOns for private servers and retail! First off, the addOns here are for any purpose. To get addOns, download Wowmatrix or the curse client. ( Just google them ) Or you can head down the http://www.wowinterface.com
1st. Carbonite - It's the best questing addon out there! Even with the new map system I still use this addon because of it's own mini map.
2nd. Gatherer. - This addOn is very cool because it records data of the herbs/minning veins that you gather on the map. You should also get the addOn Gatherer WowheadDB. It's a database for Gatherer.
3rd. Deadly Boss Mods. - It's really useful for raiding.
4th. Xpearl. - Xpearl is really cool. It's mainly for raiding frames. It also shows your portrait ( your face ) as 3d which is really cool feature imo.
5ft. Bartender. - I personaly don't use this addon but all my friends like it. It's an addon that changes your action bars around.
6th. Healbot. - This bot makes healing SO easy. ( NOTE: It's not a bot! )
7th. Auctioneer. - This addOn will make you rich. It records the auction house data and tells you what's worth buying/selling.
8th. Postal. - This is addon for your mailbox. It will pick up everything in just 1 click. ( Instead of clicking many times... )
9th. Bejewled. - This addOn is the game Bejewled, in game! Really useful when your waiting for BG/dungeon queue!
10th. Bagnon. - This will put all your bags into one.
11th. MikScrollingBattleText. - This is really cool addon, when your fighting it will display battle text in the air.
12th. Cartographer. - An extremely powerful and flexible map mod.
13th. Capping. - Capping is just another battleground timer mod with some extras. And to it's a must have for pvp people.
14th. Skada Damage Meter. - Skada is just another damage meter, my favourite.
15th. Atlasloot. - This addon is really good for private servers ( If you are gm/admin. ) It's basicaly a big database of WoW items. You can look it up, it's pretty cool.
And those were my top 15 addons. If you have any addon that you think is really cool, add it the comment box below! Thanks and I hoped this helped you!