Just off the top of my head...Brocclli, cauliflower, brussel sprouts, cabbage and collards all came from a wild cabbage plant in England.
Both my mom and dad came from farming families, each year at harvest time, they would select seeds from the best looking of the harvest and those seeds would be the next years crop.
That's how the ancients did it, each year for hundreds (probably thousands) of years they just kept selecting seeds each year from the most desireable. From year to year, the change was almost undiscernable but, in the long run, changed the corn plant into what we know today.
Lots of plants have been "domesticated" in recent times. I can think of the strawberry off the top of my head. It used to be the tiny wild berry that you can still find in fields but has been bred to be much larger and sweeter by man. See Strawberry history.