Sure thing! Picking good candidates will depend a lot on whether the last two players choose land or water nations. I'll assume at least one chooses a land nation, since there are few maps that will work well with 3 water starts.
Cradle of Dominions -- Roughly 18 provinces/player
There's a version already uploaded to llamaserver with fixed starts for 11 land and 1 water nation, so if we have that configuration, I'd recommend using that version.
Glory of the Gods (multiplayer) -- Roughly 22 provinces/player
Probably good if we have two water nations
Orania -- Roughly 23 provinces/player,
WraparoundKind of on the large side
Urraparrand -- 15 provinces/player,
WraparoundThis one would also be good for two water nations
Greek Stain -- Roughly 17 provinces/player
This one also has a version with fixed starts for 11 land nations and 1 water nation
Realm of Roaring Rhinos -- Roughly 15 provinces/player,
WraparoundAnother one with a version that has fixed starts for 11 land and 1 water nation
There are many other maps that could work, of course, but these are the ones I liked best.