What sports are most impressive for colleges?

No specific ones, depends on the school. Don't play sports just for college. Leave sports out of it, at least. Schools just want to see someone with a personality. If you play the sport that is the most supported by the school just to impress them it won't make a difference, especially if you don't really like and do it just for the school. If you have a bunch of stories to share about your fun time and your leadership and how you take charge in a less impressive sport, it is much better. Most sports take a lot of skill regardless, so all of them are impressive if you practice enough.

All sports are somewhat impressive to colleges because they typically require immense amounts of dedication and effort. However, leadership roles (such as team captain), meaningful titles (such as state or county champion), and specific awards are especially strong. There isn't any "one" sport colleges are impressed by; your role(s) and achievements within the sport are far more important.

Hope this helps :)