It doesn't need to be only 7, I think, I assume he ment higher or something o-o
idk, maybe Photons or Gimmickpuppets could work since they pop out level 8s, though for gimmicks, they need to xyzs, for Photons, xyz is optional.
I could still be wrong since he said cards to make summoning level 7+ easier, not much of cards that are easier.