You are right, most historicaql battles are with rome.

Additional Battles I would like to see:

Raphia (Ptolies-Seleukids), Cannae and Zama (Carthaginans-Romans), Gergovia (Gauls-Romans), Chaironeia (Pontos-Romans), teutoburger Wald (Sweboz-romans), the elephant-battle (galatians-seleukids), some of the battles between epeirotes and romans.

Once again, roman predominance.

Battles which I would like to see but don't know anything about:

parthian invasion of the seleukid empire
baktrian fight for independence against the seleukids
baktrian march against the indian kingdoms,
battles between different gallic tribes,
battles between romans and lusotannan
battles between romans and Getai (Decebalus)
battles between romans and casse

The problem is, that for historical battles you need quite precise information about terrain, troop numbers and composition, tactics and so on. But AFAIK there are not very many suitable sources for non-roman battles, especially for those between barbarian factions. Most of the big battles between the successor states have happened before the EB-timeline. So there will always be a roman predominance in the historical battle compartment. It's unavoidable i guess.