I see there is a lot on chemistry, math and physics. Geology topics would be a welcome addition that I would be happy to help with. Mineral names, formula, etc. would be very amenable to this type of work.
I would love to see a course on minerology and other topics in Earth science. I would like to be able to identify minerals by their formulas and by pictures.
Seconding on the mineral classification, either by picture or abstract crystal shape and coloring.
Maybe adding a memrise for identifying rocktypes like gabbro, granite and basalt?
Name-picture matching courses would be awesome for mineralogy!