Okay so my thoughts so far:
-Regieleki: Super duper fast, and looks like it could be really good with a Choice Specs, since it barely needs to invest in its own speed, and can run a Special attack boosting nature. Rising Voltage (in terrain), Volt Switch, Electro Ball, all sound like good options, though I expect it to have a similar movepool to Xurkitree, so Energy Ball and Dazzling Gleam maybe.
-Regidrago: A worse version of Guzzlord, but boy do I love my bulky fat mons. Loving it so far, and if it gets Dragon Dance, it could actually be decent, seeing as its speed is decent and has good attack, plus its sky high HP allows it to take at least one attack from pretty much everything. Maybe it gets Recovery too?
-G-Articuno: Looks promising, as it has good speed, great special attack which is further boosted by competitive. It is kind of a better Jynx at this point.
-G-Zapdos: As expected, the thing is great. It has really good bulk, great attack, and a good speed tier. If it gets actual good moves, it will almost certainly be a dominant force in OU.
-G-Moltres: Honestly, I'm loving its stat spread (I love me some bulky mons), and it seems to be a special defensive Mandibuzz. I'm hoping this thing gets some great tools to take advantage of that bulk (like Nasty Plot to go with Berserk), so that it has options and doesn't just play the Mandibuzz role.
-Ice Horse: I was really looking forward to a fast ice attacker, but alas, it wasn't meant to be. This thing seems to be another version of Avalugg, except with less physical bulk and more physical attack. It will hit like a truck, but its typing coupled with its speed spells doom. I love Ice types though so I will definitely run it.
-Ghost Horse: A really good mon, with decent bulk, amazing special attack (plus a moxie equivalent) in addition to its amazing speed tier. This thing will be great if given some good coverage.
-Calyrex: I was hoping it was stronger, like around 600bst, and was hoping it would be bulkier. But it will be fun in lower tiers, and hopefully has a good movepool.
-Calyrex Ice Rider: This thing is bonkers, as it has insane bulk and hits like a truck. But it is severely held back by its typing, though its movepool could really save it. If normal Calyrex gets Leech Seed and/or Trick Room, it could have a niche for itself.
-Calyrex Ghost Rider: This thing is straight up insane. Like this is Mega evolution level insane, but this thing can hold an item. I guess after the insanity that was Zacian-Crowned, I should have expected something like this, but I honestly though Calyrex would reach 620 at most for bst in its forms. This thing hits like a TRUCK, and is super duper fast for the tier (the fastest?). Yveltal it going to be an absolute need on every team.