>>85300934Searching the top level tier for DC (which is DCU, but a few things still fall out), the top for COMMENTS (which doesn't mean most reviews since some are just keysmash crap and in some cases the author responds to every review, so if the story legit has 50 comments and she respond to every one that means 100 comments where as two other stories might have legit 55 or 75 comments, etc.).
But the rank for comments and word counts would be the same:
Oliver Queen/Felicity Smoak (7587)
Clark Kent/Lex Luthor (5397)
Clark Kent/Bruce Wayne (1912)
Tim Drake/Jason Todd (1550)
Barry Allen/Leonard Snart (1408)
If you search just by Bruce, his top relationships are:
Clark Kent/Bruce Wayne (2390)
Dick Grayson/Bruce Wayne (821)
Selina Kyle/Bruce Wayne (519)
Jason Todd/Bruce Wayne (400)
Joker (DCU)/Bruce Wayne (219)
Diana (Wonder Woman)/Bruce Wayne (214)
The top ten stories in size under Clark Kent/Bruce Wayne are over 100K words. The top 50 are still fairly close to 50K words being about 47-48K at the bottom end (##s 44-50).
Clark and Diana doesn't even 100 stories with that pairing. Two of the longest are over 100K with the longest over 200K words but #3 barely hits 43K.
Ao3 is the largest board of it's type and gets the most traffic. Many people on Live Journal, tumblr and FanFictionNet cross-post there because of it.