Help request for roll20 marketplace maps

[Ju5t1n88]

I have a module that I'm nearing completion for the Roll20 marketplace.
A problem I'm having is, the maps I have made are, shall we say, not interesting enough.
These started out as maps created with multiple tile sets @ Pyromancers. When I decided to convert my module for sale on Roll20 I discovered that they weren't using commercially available tile sets. They did however have some tilesets that I was able to get permission for, but they weren't as extensive, especially in the 'nature/cavern' realm. I have tweaked them a big to try to get rid of so many straight lines, but I'm fairly limited in creating new. I feel I have a bit of a knack for editing images but, creation is not my strong point.
I'm here in hopes that someone can take my gimp files and add some flair, at at least help me improve it on my own.
I would be ecstatic if I could simply acquire some tile/sets that I could use commercially.

Thank you for viewing and much thanks if you can offer any assistance.

example 1

example 2


I don't believe i have enough posts so please respond to:
jjhighberger@gmail.com