I think that any campaign except Taus would be fun. Orks, Chaos, Eldar, Dark Eldar. By the way, I have a question: would an all eldar campaign in which the player can control craftworlds, corsairs and Deldar make sense lore-wise? (Please excuse me, I'm kind of new to the lore)
@aram_thehead there is a faction that worship the newly forming aeldari death god yeanead, they are the ynnari and they are comprised of all eldar factions. they are also on good terms with the imperium of man. at the moment they are not large enough for this kind of conflict but if they completed their goal of collecting the chrone swords they would be in a good position to unite all the factions of the eldar.
@aram_thehead ya they think if the death god fully forms or wakes or whatever hes currently in a limbo right before birth. the eldar think when he is born he will destroy slanessh and save them from damnation but for that to happen basically all the eldar have to die, the leader of the ynnari who believes she was contacted by the ynnead began a quest to get the chrone swords to hasten his birth or whatever you want to call it so not all the eldar have to die first. chone swords fyi were created from the fingers of one of the other aeldari gods before slanessh killed her so they apparently have some power to be used in the scheme of things.
@imptastic I had noticed that there was this sub faction that had the same name in all 3 eldar races. I thought it was a mistake when I first saw it, now it makes sense
There's also a faction called the Harlequins that absolutely every Eldar faction both respects, and works alongside. They're not in the game at the moment, which is a shame, because their ships would look rainbow FABULOUS.