Avgas 80/87 is used in low compression ratio aircraft engines, and contains little or no lead (up to .5 grams of lead per gallon is allowed, but none is required). It is red in color, and should not be used in any automotive engine due to a low motor octane number of about 80.
Avgas 100/130 can be used in some automotive engines. It has both research and motor octane numbers slightly over 100. Avgas 100/130 is green in color, contains four grams of lead per gallon, and is becoming hard to find.
Avgas 100 LL (the LL stands for "low-lead") contains two grams per gallon, half the lead contained in the avgas 100/130 it was designed to replace. It has research and motor octane numbers very similar to 100/130 avgas. The color is blue. This product sometimes has a high level of aromatics.
Avgas 115/145 was developed for high performance piston aircraft engines used in World War II and the Korean conflict. It is very hard to find today due to lack of demand, and is usually only produced on special order. The color is purple.