There's four.

San Magnolia (Lena and Annette). Giad (all the surviving 86ers and Frederica). Wald which was mentioned at the beginning of the big assault because the Federacy keeps in touch with both. Roa Gracia (same), but I think San Magnolia knew about them too in the classrooms, so they're presumably way bigger.

Key point is that San Magnolia and The Empire of Giad used to both be really quite big. San Magnolia we knew about, and the latter is implied by Frederica's retelling of her family and Kiriya's last stand.