Guess I really never looked at the mold on coffee grounds as anything other than the initial stage of the breakdown process. Anyone with mold allergies might regard it in a different light.

Aspergillus mold is white and gray and appears fluffy or feathery and I've seen that mentioned in conjunction with the breakdown of moist coffee grounds.

Rhizopus is the common bread mold.

Although some people could make an educated guess, molds can only be positively identified with a microscope.
Bluish-green to green molds are usually Penicillium or Aspergillus. Black to brown-black molds can be Aspergillus niger, Alternaria alternata, Cladosporium herbarum, Cladosporium sphaerospermum, or Stachybotrys chartarum (a highly toxic mold). Reddish or pink molds are usually species of Fusarium.