Lettuce can also be very prolific when allowed to seed. I currently have a fight for garden dominance between the parsley and the lettuce which seeded themselves this year.

Garlic chives are a strong contender to be in that list too!

E: also agree with Rusty’s assessment of lettuce. Have seen it grow in gravel pavements and get quite hectic under a downpipe. Mizuna (and some other mustards) can be like that too