Nature-based High-resolution Background Pack (100 images)
https://game-material-store.itch.io/nature-based-high-resolution-background-pack…
Dungeon High-resolution Background Pack (100 images)
https://game-material-store.itch.io/dungeon-high-resolution-background-pack-100-…
Cyberpunk & Sci-Fi High-resolution Background Pack (100 images)
https://game-material-store.itch.io/cyberpunk-sci-fi-high-resolution-background-…
Source: itch.io