I have caught quite a few so far and have been going back to get the ones I missed! So far from memory I have: Golem, Rhyperior, Walrein, Snorlax, Rapidash, Ponyta, Electivire, Mismagius, Probopass, Gliscor, Goodra, Zoroark, Luxray and Qwilfish. I think I also have a few others like Kricketune, Magikarp, Pichu and Bidoof. Some of them have been much easier to catch than others. I had to keep resetting others like alpha Electivire because it would run out of PP and struggle before I could catch it :( I like trying to catch them in regular Pokeballs but I just gave up and threw Ultra Balls at Electivire so I could get it over with.
I also saw an alpha Sylveon in a space time dimension and I was so excited to try catch it but I wasn't able to battle it because I got distracted catching Jolteon... won't be making that mistake again. :D