If so you may be able to determine their origin just by their color. Coolant is frequently bright green. Oil is brown. Power steering fluid is typically red. Brake fluid is tan, nearly clear.
Gasoline is clear and has a distinct odor.
If there is plain water on the ground, touch it. If it's icy cold, odds are that it is condensation from your air conditioning system and is nothing to worry about. Any such emissions from the engine indicate trouble. Black or blue smoke from your exhaust may indicate a problem, too. Normal deposits on your tailpipe would be the color of hot chocolate.