Here's a bunch of potential ideas, with brief comments on most:
African:
-The Bantu migrations, a series of "wave-advance" migrations in which the Bantu culture spread across sub-Saharan Africa.
Near East/Africa:
-The migration of the Israelites from Egypt to Canaan. Book of Exodus has some pretty specific geographic information in spots, and you can definitely find some interesting stuff on old cities like Jericho.
Polynesian/Oceania:
- The Polynesian migrations generally. A huge explosion of sea-based migration.
- The Hawaiians. Depending on how exactly you're defining "ancient," the migration-era Hawaiians are a great one (though much later, historically, with the first migratory wave in/around 500-600, and the second wave, the major one, around 1000). Check out the introduction in "The Legends and Myths of Hawaii," by His Hawaiian Majesty, King David Kalakaua. It's based on old scholarship (around 1888), but it should give you some ideas about the Hawaiian migrations. There's some really interesting legendary material as a result of these migrations in the book, as well.
European:
- Goths:
-Tervingi
-Greuthingi
-Ostrogoths
-Visigoths
- The Vandals (and eventually the Alanni who joined them)
- The free Alanni (under Goar, who started in the Caucasus and ended up in what is now Brittany, France, while fleeing from the Huns.)
- The Huns (easily the biggest, most epic migration story ever, assuming that they and the Xiongnu (pronounced something like Shung-nu) in Chinese sources are the same people. Check this out on Wikipedia, which has a pretty decent article on the Hun/Xiongnu theory, and the arguments both for and against.)
Asian:
-Yuezhi (these guys are interesting because they show up in both Chinese and Western European ancient writers.)
-Wusun
Unfortunately, I'm not aware of any specific major migrations in the Americas before the modern period. I know the migrations were there, but I don't know what they were.
If you want to do some group in Europe during the period from AD100 to AD1000, and if you have time (unlikely, but if you do), I'd strongly recommend reading "Empires and Barbarians" by Peter Heather, which basically analyzes migration and state development in the late ancient and early medieval world.
Don't know if this helps, but hopefully you can get some ideas from it.