There are 14 different types of rubble mushroom. They come in 6 different hues - plain, four shades of grey, and black. Mushroom types 8 and 14 are stackable. None of the mushrooms can be dyed or rotated.

Hue 0 Hue 986 Hue 985 Hue 984 Hue 987 Hue 1175
Type 1 IMG-bbf-0 IMG-bbf-986 IMG-bbf-985 IMG-bbf-984 IMG-bbf-987 IMG-bbf-1175
Type 2 IMG-cbf-0 IMG-cbf-986 IMG-cbf-985 IMG-cbf-984 IMG-cbf-987 IMG-cbf-1175
Type 3 IMG-dbf-0 IMG-dbf-986 IMG-dbf-985 IMG-dbf-984 IMG-dbf-987 IMG-dbf-1175
Type 4 IMG-ebf-0 IMG-ebf-986 IMG-ebf-985 IMG-ebf-984 IMG-ebf-987 IMG-ebf-1175
Type 5 IMG-jbf-0 IMG-jbf-986 IMG-jbf-985 IMG-jbf-984 IMG-jbf-987 IMG-jbf-1175
Type 6 IMG-kbf-0 IMG-kbf-986 IMG-kbf-985 IMG-kbf-984 IMG-kbf-987 IMG-kbf-1175
Type 7 IMG-lbf-0 IMG-lbf-986 IMG-lbf-985 IMG-lbf-984 IMG-lbf-987 IMG-lbf-1175
Type 8 IMG-mbf-0 IMG-mbf-986 IMG-mbf-985 IMG-mbf-984 IMG-mbf-987 IMG-mbf-1175
Type 9 IMG-nbf-0 IMG-nbf-986 IMG-nbf-985 IMG-nbf-984 IMG-nbf-987 IMG-nbf-1175
Type 10 IMG-obf-0 IMG-obf-986 IMG-obf-985 IMG-obf-984 IMG-obf-987 IMG-obf-1175
Type 11 IMG-pbf-0 IMG-pbf-986 IMG-pbf-985 IMG-pbf-984 IMG-pbf-987 IMG-pbf-1175
Type 12 IMG-qbf-0 IMG-qbf-986 IMG-qbf-985 IMG-qbf-984 IMG-qbf-987 IMG-qbf-1175
Type 13 IMG-vbf-0 IMG-vbf-986 IMG-vbf-985 IMG-vbf-984 IMG-vbf-987 IMG-vbf-1175
Type 14 IMG-wbf-0 IMG-wbf-986 IMG-wbf-985 IMG-wbf-984 IMG-wbf-987 IMG-wbf-1175

Six of the mushrooms in the above list can also be assembled to form a mushroom ring:

Hue 0 Hue 986 Hue 985
IMG-obf-0 IMG-obf-986 IMG-obf-985
IMG-nbf-0 IMG-dbf-0 IMG-nbf-986 IMG-dbf-986 IMG-nbf-985 IMG-dbf-985
IMG-cbf-0 IMG-ebf-0 IMG-cbf-986 IMG-ebf-986 IMG-cbf-985 IMG-ebf-985
IMG-bbf-0 IMG-bbf-986 IMG-bbf-985

Hue 984 Hue 987 Hue 1175
IMG-obf-984 IMG-obf-987 IMG-obf-1175
IMG-nbf-984 IMG-dbf-984 IMG-nbf-987 IMG-dbf-987 IMG-nbf-1175 IMG-dbf-1175
IMG-cbf-984 IMG-ebf-984 IMG-cbf-987 IMG-ebf-987 IMG-cbf-1175 IMG-ebf-1175
IMG-bbf-984 IMG-bbf-987 IMG-bbf-1175

The different hues of grey can be very difficult to distinguish visually, but there is a difference.

hue 986 hue 985 hue 984 hue 987

Pinco's UI can help you get the hue number for any given item.