This is fantastic work! I really like the aesthetic.
I feel though like this is missing some water tiles. You know, for lakes and and the ocean. Something to better define the boundaries of the play area.
Awesome! Thanks a lot.
If I could also suggest a "river start" and "river end" tiles to go along with that, to keep the river animation going, that'd be fantastic.
Edit--
By which I mean, a way to connect the water tiles to the river tiles in a way where the animation of the river connects to the water tiles and disappears seamlessly.