I'd say there's a fine line between "friends" and "connections". A chosen list goes as such.

Company lablemates - Actresses:

Ha Jiwon (Secret Garden, King2Hearts; the one who danced with AA in their debut stage)

Oh Yeonseo (My Husband's Got a Family, Babyfaced Beauty)

Actors:

Lee Junhyuk (Equator Man, City Hunter, I am Legend, Secret Garden)

Lee Jongsuk (School 2013, High Kick! 3; the one who taught Kimchi his "puing puing")

Revealed celebrity friends:

U-Know Yunho (Woosang was DBSK's backup dancer in the past)

Ulzzang Kim Minjun (Juwon most probably met him on the job or through mutual connections)

Other relationships:

Daishi Dance (Japan's famous producer; he first saw Aoora)

There are numerous more company lablemates and others, but these are the ones who stood out to me the most :)