I beat the game a week or so ago and have seen all the mons now, so time to contribute to this thread.
For the first time, I tried to go into the game without a mostly pre-planned team in mind, aside from a few mons I really wanted to use.
In a different thread before the game came out I mentioned how I was considering using a different team for each story. This was motivated by the reveal of Armarogue and Ceruledge, both of whom I wanted to use, and by the fact that the leaks informed us that Fuecoco3 would be fire/ghost. Due to the similarities, I didn't want to use them all on a single team.
Another possibility was to just rotate through a lot of mons during the playthrough, so I actually started by doing that. This is because my first goal for the game was just to catch a bunch of mons that I had managed to not see yet. Functionally that meant deciding to do the Titan storyline first, since I had managed to not see Bombirdier or a clear image of Orthworm yet (and maybe Dondozo/Tsatsugiri, but I think I accidentally saw those before I made it to them).
On the way I started catching mons to try and evolve them along the way, but there were way too many new mons and I wasn't evolving them fast enough, and I eventually realized I wasn't rotating and was just using a bunch that I liked and was hesitant to swap out when I caught a new mon, so I decided to proceed with the 3 team plan after all. I think Tarountula was the easiest to evolve, making Spidops perhaps the first Pokemon in memory that I had seen for the first time within the game, which was cool, although it didn't save Spidops from getting boxed.
Path of Legends:
I decided I would use my starter, Fuecoco (despite the fact I peeked at Skeledirge and was unimpressed with its mouth fire looking like hair on a balding clown). Early on I caught a Wooper, Pawmi, and Nymble early on, and I nabbed a Caspakid-Rock from a raid. I hadn't seen Scovilian clearly, so I kept it on board and it eventually just stayed on my team. I came across Tinkatink near some ruins unexpectedly, so I caught it there and added it to my team. There were some other mons in there that got boxed because they weren't evolving fast enough and weren't as cool (Spidops, Smoliv, Fidough, Mastochiff). With this, I had my team for the Titan run:
The MVP of the team was Clodsire. Its poison point ability was basically the key to beating Titan Great Tusk and the Sushi duo. I was so underleveled because I was only doing the one storyline and avoiding trainers. I didn't realize until the last fight just how ground weak this team was. I had to grind a little bit to level up and visit the picnic once which was enough to get the affection bonuses, which came in clutch once or twice during the battle. Better than grinding more. :P (I didn't use picnics for the next two stories, but here I was overly hopeful that I might be able to get into part of area zero to catch Flutter Mane, but nope).
Starfall Street:
After completing Path of Legends I decided to take on Team Star. I decided I would use Armarouge for this run. I boxed my team and grabbed a level 14 Charcadet I caught early in the game. Other than this Charcadet, I opted to only use mons that I caught fresh during the run, instead of just using things I had in my box. I decided that this way my team would form more spontaneously, and would be more interesting than if I totally planned it out.
At this point, I still hadn't seen Smoliv3, so I decided to catch a new one and keep it on the team now that I'd used Scovillian. While running around somewhere I saw a Nacl and decided to add it to the team. I'd been spoiled on Garganacl at this point, but I thought purifying salt was neat and I wanted to try the mon out. On my way to fight Giacomo as the first base, I decided I probably wanted a few more mons on my team, so I tried catching a new Bombirdier but they all kept mementoing on me, so I gave up. Instead, I caught a nearby Mankey. I wasn't entirely sure I wanted to keep it until it evolved into Annihilape, but I did want to make sure I added a ghost type eventually, and then Mankey turned out to be pivotal in the Giacomo fight, so I kept it around. After going through Mela and heading through Levincia, I ended up catching a Wattrel and a Varoom, which formed the last two mons added to my team. I had tried to catch a level 28 varoom, but it blew up, so I caught a level 20 instead, which turned out to be lucky for me. In my previous run I had not realized that Titan/Starfall badges did not count for obedience, so I must have caught all the Pokemon below level 20, and if I'd caught the level 28 varoom it would not have obeyed me. ...unfortunately wattrel was caught at level 23, so I had a disobedient seagull for the rest of the storyline. (I was stubborn and did not want to do a gym just to get it to obey). It was at least useful for pivoting... After evolutions, the final team was
Arbolivia was the MVP of this team. Once again underleveled for the final fights, it came in clutch with growth and giga drain. In the final fight hyper potion spam allowed it to stall out 20 aurora beams and then get to +6 special attack to tear through the rest of the team.
Victory Road:
For the final path, I went in having decided on 3 of my mons already: I wanted to use Sprigatito, Ceruledge, and Palafin. Thanks to trade codes I was able to get a Sprig to breed and a malicious armor for later use. I started only with Sprig this round, and kept my rule to only catch new mons to use on my team. I got a new Charcadet from the area East of Mesagoza, and caught a Shroodle, not sure if it would make it to the end, but wanted something to pad out the team for now. I took on Brassius and then Katy, and then made my way back over to Levincia to pick up a Finizen. I think around here I also picked up a Cyclizar and at some point a Flamigo (maybe I caught Flamigo early on). It was around now I was starting to think about what I wanted to have on the final team. I noticed I had a bit too many physical attackers at this point, so I decided to add one or two special attackers. I knew Glimmora was a special attacker, and I knew where to find it, so I decided I would head to the pass and catch it there. Around this time I also happened to notice that in one of my boxes I had a recluse frigibax! I had been considering Cetitan over using the psuedo, but the rarest mark was too tempting, so I decided I would add this to my team after catching a new Frigibax in the pass. (That all went well, but glimmets kept blowing up on me, so I noticed I had an outbreak over by the psychic gym, so I went over there to catch one). For the final member of the team, I knew I still wanted one more special attacker, and I noticed that at this point I had collected 999 Gimmighoul coins, so I decided Gholdengo would be the final member. I had to catch a level 50 Gimmighoul because I didn't find a level 30ish chest respawn, so it took a bit before the wacky-waving inflatable tube man would obey me. Somewhere along the line a helpful stranger from the Smogon discord helped me evolve Finizen into Palafin.
[Special interlude team: for the Ghost-gym battle I decided to only use the four ghost types I had from these 3 teams].
So, the team I would use to finish off the Victory Road storyline came out to be
It's hard to pick an MVP for this one, because in this run I started battling trainers, so by the final four gyms I started out-leveling the opponents. I was a little bit underleveled for the E4 and Geeta, but not enough that they posed too much of an obstacle. (The first two E4 were easy, but
Larry put up a good fight.
I was a bit underleveled for the final battle of the storyline, though, enough that I got bested first time, though it was close. Managed to eke out the win the second time.
I also used this time for the final storyline, since there wasn't a lot of opportunity to swap out anyone for the paradox mons.
Overall, I'm pretty happy with the selection of mons I ended up using, and especially how unorthodox my first two teams where. I hope in the DLC there are some substantial new stories that will give an opportunity to use the Paradox mons or more new mons.
EDIT:
I had been putting off doing the postgame until I found out that you need to do it to unlock 6 star raids. I had originally been considering raising teams of each type to take on each gym leader with their own type, but given that they're all level 65ish I decided nuts to all that grinding, so I just put together a team using paradox mons. I didn't want to just make a copy of Sada's team, so with Nexus' help from the Wifi forum I caught all the Violet paradoxes with my own OT, and then put together the following mix of paradoxes to take on the gym leader rematches and the ace academy tournament:
I have to say, I quite like the composition of this team in terms of types and the balance of past and future paradoxes. It was quite fun to use, and the rematches + ace academy tournament were meaty enough that it felt like I spent enough time with the mons for it to be regarded as a genuine team alongside the other three I used. (This was partly achieved by trying not to just fly straight to all of the gyms and instead traversing the world, battling higher level mons or missed trainers along the way).