The materials are completely procedural.

It works in Cycles and EEVEE.

Ideas for own Customization:

You can add Mapping Nodes, for example, directly after the Texture Coordinate Node or on a Vector Input or Output. I did not add more Mapping Nodes because I did want to overload them, and for instance, some are relatively generic, like after the Texture Coordinates to get a Base Rotation or change the Scale, which can be easily done if someone needs it. First Pack has some more of these start Mapping Nodes. The reason is that it affects the transitions better.

You can add Mapping Nodes, for example, directly after the Texture Coordinate Node or on a Vector Input or Output. I did not add more Mapping Nodes because I did want to overload them, and for instance, some are relatively generic, like after the Texture Coordinates to get a Base Rotation or change the Scale, which can be easily done if someone needs it. First Pack has some more of these start Mapping Nodes. The reason is that it affects the transitions better.

You can change the Modes of Procedural Nodes like Voronoi. (The Animated Blender File makes use of this.)