It is similar to square dance, and the contra dances we went to out in California would occasionally do a square dance or two. Contras are simpler, and long lines of couples.

Waltz and the list you have yes, are set patterns you elaborate from. Modern dance is structureless. Contra is more structured than waltz and the like - more of a pattern, a lot less knowledge and ability required. Honestly, it's a geek's dance! Karl wouldn't do freeform dances with me, but he can do this. I bet Miles could, too.