If we have to deal with "Iconic" meaning established by CA, to chooce more four factions will be difficult. There alot of very "Iconic" factions to allow to be playable :
1. Ptolomeis
2. Saleucid
3. Pontus
4. Gallic Tribes
5. Numidia
6. Pergamum
7. Greek League
Just to name some of them.