Golden Boy
Neon Genesis Evangelion
Azumanga Daioh
Excel Saga
Puni Puni☆Poemy
Super Milk-chan (there's two dubs, watch the one where Tetsuko, the robot, sounds like a smoker)
Nerima Daikon Brothers
Blue Seed
Nadia: Secret of Blue Water
Dragon Half
Ushio & Tora (their successor, Sentai, did a dub for the TV series and made sure Brett Weaver returned as Tora)
Ghost Stories
Cromartie High School
Nurse Witch Komugi-chan
Di Gi Charat
Gunsmith Cats
Princess Tutu
Gantz
Shadow Skill
AIR
Kanon
Chrono Crusade
Colorful
New Cutey Honey
I'd also like to add Martian Successor Nadesico (this dub is a must-watch), Aura Battler Dunbine, Sakura Wars, the Sonic OVA, Mighty Space Miners, Gasaraki, Power Dolls, This Ugly yet Beautiful World, Magical Shopping Arcade Abenobashi, Super Atragon, Kino's Journey, and Macross (both the original series and DYRL, sans Robotech references). I think they may have done Megazone 23, but I'm not sure. The dubs of Nadia and Princess Tutu are both great as well. Some of their dubs I haven't seen yet but would like to see are Zone of the Enders, Rahxephon, SIN: The Movie (apparently the entire movie was commissioned by ADV), Casshan: Robot Hunter, Ganbare Goemon, Hakugei Densetsu, Dai-Guard, Mazinkaiser, Gravion, Neo Ranga, and Kitty's Paradise (the latter two have very short episodes by the way). Other good non-ADV dubs are Samurai Pizza Cats, the Pioneer Tenchi Muyo dubs, and DIC Sailor Moon.
Of all the ones I listed above, I most highly recommend Gasaraki, Aura Battler Dunbine, Mighty Space Miners, and Super Atragon. Super Atragon is one of my all-time favourite OVAs. It has boring mechanical design, but excellent animation and a very interesting story that I think inspired a few conspiracy theories IRL. It's also one of the few non-pornographic anime done by Phoenix Entertainment, the Giant Robo studio. Mighty Space Miners has incredibly detailed animation and a good main character, but it ends on a cliffhanger because the OVA series was cancelled. Aura Battler Dunbine is a Tomino show, so it can get very dense at times (keep in mind this is the dumbed-down toyetic version of his Wings of Rean novels, so it's still just scratching the surface), but it's thought-provoking and you'll definitely get something out of it. Finally, Gasaraki is another smartly-written mecha anime with elaborate politics, including the elites stoking a race war.