I think there will be new decks from Fates collide itself:
- Carbink/Regirock/Zygarde
- Alazakam/Bats/Wobbuffet
- Serperior
Not sure how competitive these decks are, need lots of testing.
For old decks, they agin some supporter in the new set:
- NM, got Mew as a backup attacker.
- Manectric/Bats, got Mew to use overrun for free, or assault laser for a single lighting energy, same goes for Sceptile/Bats unseen claw.
- Trevenant, got random recevier to increase to chance of T1 Wally.
- Megaman, got Glaceon EX to play alongside with Jolteon EX and Regice, it's got to be annoying.
- Mill decks (i.e. Durant, bunnelby, Houndoom EX), Durant got Mew for a sinlge raindow energy attachment to attack, also got team rocket handiwork for more discards.
I am mot sure whether Barbaracle or Marowak would be commonly used, as they are both situational against certain decks only. A 2-2 line with maybe float stone take up lots of space, hurt both consistency and speed.
I am quite sure Lucario, Genesect EX, Kingdra EX, Audino EX and Moltres break are not competitive though, maybe Altaria EX would join this group too.