Allakhazam's List - Tacitus' original Campsites listing from Allakhazam, and inspiration to this compilation. It was last updated back when Treasures of Aht Urhgan was released by FFXIFiresoul.
The Vana'diel EXP Guide - Ayrlie has compiled a massive collection of potential campsites and mobs throughout Vana'diel. However, level/camp specifics are still a little rough in places. It's a great source of inspiration though, should you ever feel like taking your party out to someplace...different. ^^
MysteryTour's List - MysteryTour's listing of campsites. Once highly relied on, it is no longer updated and is very outdated. Still a good place to look for "alternate" or "old school" camps, should the urge arise.
Tororoto Mob database - Japanese website- enter in the highest level in your party, and query a database to bring up all the mobs that you could potentially xp off, and even see the xp/kill they give!
Other leveling locations
Campsitarus isn't the only leveling resource out there- here are some others that I have found!