Bases for sauces?

[eveglass]

I cooked a decent breakfast-for-dinner tonight, one of the few things I know how to cook consistently well. Simple but effective: scrambled eggs with onion and garlic, accompanied by baked beans on toast. Yum!

Doing all this cooking (ha.) made me think of a question: what sort of things are generally used as bases for sauces? So far I've come up with:
- milk and cream (white sauces)
- tomato (red sauces)
- gravy (brown sauces)

Is there anything else that can be used as the base for a sauce, or is that about it?

Thanks, cooking friends! I know you'll come through on this one!

Edited to add: I suppose something like a thick vegetable puree could be used as well, to make a... green sauce? Yes? No?

Comments

[tygrbabe.livejournal.com]

pasta can also be tossed with pesto (basil sauce) or tapenade (olive paste) and a really simple alternative to tomato sauce is roasted red or yellow peppers: cut peppers in half, de-seed, put skin up on a lined cookie sheet, drizzle with olive oil and bake 'till some black spots start appearing. then puree for sauce (you can peel them before if you like, after baking, the peel comes off easily, makes a smoother sauce).