Modpack Info
First and foremost, you're free to use Botania in a modpack, just make sure to keep the license in mind.

Here's a few modpacks that have botania on them. These are in no particluar order. I'm not listing every single of them though, because that'd take a lot of work.
Note: Aside from the official pack, none of these packs are officially endorsed. They are simply included here as examples of common packs that use botania.