Heroic Maps gives you more options for your gaming terrain with the release of their modular caves kit.
From the release:
Modular Kit: Caves is a printable dungeon tileset compatible with any RPG/Dungeon-Crawl game. It can be used as a standalone set, or combined with any same-scale tileset.
Modular Kit: Caves comprises 64 different tiles that can be printed multiple times and arranged in limitless combinations.
PDF printable sheets, with both gridded and non-gridded versions
A set of 300dpi full size png files, for poster printing or VTT.
A sheet of wall and floor textures, for custom wall layouts
A set of sewer-cave and dungeon-cave transition tiles
This set is compatible with the 2.5D crafting system, a crafting technique for making dungeon tiles more than 2D but not quite 3D. The 2.5D system was created by DM Scotty (Google his forum for tips)