The Aztecs used guacamole in the 1500s, probably made from peoples hearts. They were savages who used to rip out people hearts like in Temple of Doom. Freaking Indians. Then the Spanish conquistadors (thats Spanish for saviors) came and learned how to make it with tomatoes instead of hearts. They brought it back to Spain where it lived happily ever after.
Avacado, tomato, onion, lime, lemon juice are very common. Also you can use cilantro, garlic, black pepper, black beans, jalapenos. But all you really need is like 3 avacados and some lime packets and your good to go.
One time Kraft was sued by some lady because there guacamole didnt contain enough avacado. The case of Lady v Kraft went all the way up to the Supreme Court before Chef Justice Rehnquist realized the plaintiff was black and dismissed the case WITHOUT prejudice because he is NOT racist. He then told her she was NOT allowed to buy any houses and should go live in the jungle with the rest of her people. His majority opinion was joined by Justice Clearance Thomas.