Adding new creatures and new towns is something I personally find as one of the strong sides of the VCMI project. Even tho I am not experinced in modding from lurking around forums I realize that the old erm scripts are not very supportive for this feature and its something that the player base wants.
Here is a list of towns I have seen that I think are worth mentioning and hope to see them all in one place as a single mode.
Hota’s Cove town a completed pirate faction, done like a pro
Bastion town I think this one is dead but I am not sure, anyway best town screen in h3 by my opinion.
Hota’s Kronwerk an incomplete town from the hota team, winter theme, dwarf and nordling looks nice hope to see it done
Hota’s citadel portraying a human religiosly fanatic race.
Groove town even tho models are a rip off from warcraft’s night elves its one of the few that has been completed
I am probably missing a lot of them but these are the only ones that caught my attention if you know more towns please mention them it would be nice to have them all in one place.