Which ones would it be?
Mine would be Steel from TF2:
[spoiler]https://i.ytimg.com/vi/DvptDY8ivtw/hqdefault.jpg
[/spoiler]
It has 2 routes for attackers to choose, might be hard to navigate at first, but it provides fun tactical choices.
And of course pretty much any other attack/defend map from TF2, with slight modifications wold be nice.