Just found out about this format and I'm in love with it. You seem so limited with your choice but you have so many creative options. I have not seen any decks with this format at all so this is me making a deck completely blind.
The combos I have are Emolga getting other pokemon with the attack Nuzzle, and Dedenne and Pachirisu, have this attack, and they are used to stall and waiste time so I have setup my other pokemon but I can also snipe my opponents pokemon using Dedenne with Nuzzle Shot.
Morpeko and Togedemaru are for more stall, but Morpeko can snipe their bench and Togedemaru can do decent damage.
I saw Yamper and was like that is a funny ability and wanted to use it, and thought it worked well with getting pokemon. I didn't think he would be too useful unless I had Boltund in the deck though. I think a nice combo is using ball guy to get a pokeball, greatball, and a level ball or quickball (look for Yamper in your deck when doing this, or for all your pokemon) then use both greatball and pokeball, if you get yamper from them than great, put yamper down to get the ball back from the discard pile using his ability. (this part was too long)
I like the Minun Plusle combo, get Minun, use Call for Family and get a Plusle, since you use an attack with Minun last turn your going to do 120 damage killing most things that early into the game. Minun will have an energy on them when using his attack and you can use that energy to retreat into the Plusle.
Then I have have supports that do the same thing but with different names or similar things.