Check out my new Backgrounds pack. That fits most mobile games .
It have a plenty of themes
Ancient City ruins, Ancient Temple, Animals Farm, Aztic Temple, Crystal Cave, Crystal Forest, Dark Cave, Dark Forest, Dark Sewage, Desert, Fantasy Candy World, Fighting Arena, Futuristic City, Graveyard, Green Forest, Hallowen Horror House, Jungle, Medieval Castle, Mountains, Mushroom Village, Rain Forest, Seaport, Volcanos, Winter Cave.

For every theme you will find both Portrait And Landscape 

I tried my best to de-AI them in post processing ;)
Check Them Out: https://mnasr.itch.io/game-assets-pack-vol1