i was thinking koko with flying flip that also works with the dce part and a nice thing to get rid of weak pokemon like non gx pokemon.
maybe meganium from lost thunder?
I made a Altaria deck that is post rotation. I did not rely sometimes on a partner so here it is
1 latios prism
1 volcanion prism
1 marshadow (let loose)
1 Tapu lele (non gx)
1 Altaria (fight song)
3 altaria gx
4 swablu
12 Pokemon
4 mysterious treasure
4 nest ball
1 rescue stretcher
4...