Editing WoW:UI beginner's guide (section)

=== Addon packages ===
If you look around the forums a bit, you may see names like Titan Panel, [[Cosmos (AddOn)|Cosmos]], and CTMod popping up. These were major AddOn packages that contained a large number of UI AddOns. Their authors often working in teams were respectable members of the WoW community who worked hard to create useful AddOns, and have bundled them together into one easy-to-use package.

Feel free to use any and all of these packages. They are legal, Blizzard allows and encourages their use, although you won't get technical support from Blizzard if something is wrong with them. There are many of these around, download and try a few of them and see if you like them. Usually the authors make these packages highly configurable so that you can adjust them to your needs.

Note: a lot of these major AddOn packages conflict with each other, so you won't be able to use them together.