All version 1.13+ are based on the Rift Mod loader.
This is a simple mod I created in an attempt to figure out how to get the Altered Fabric block from the mod Dimensional Doors working. It adds a single block that comes in 16 colors that looks like a perfect void and glows.
The recipe for the blocks are a block of iron, glow stone, and the dye of the respective color you want. This will create 8 blocks of that color.
