Alright let's talk about these shall we!!
Leafeon: It's always been my favorite eeveelutions and this one is pretty good. It's good for those VMAX grass decks that just need one extra energy attached turn 1. I'm looking at this paired with Rillaboom VMAX. Aside from that, there's not alot of other grass VMAX decks. Anything else has Cherrim.
Flareon: Don't care if you are single strike. This is bad. Maybe if it's VMAX is pretty good. Other than that we have signficantly better fire type Single strikers
Vaporeon: I love this pokemon too...but sadly, just not worth it. Even if it has Rapid strike support. Empoleon is better in almost every way.
Glaceon: Well we'll have to wait and see how good the VMAX is because that's all it has going for it. Being weak to steel is already a huge red flag.
Jolteon: Also a hard pass. Unless the VMAX is pretty good.
Espeon+Espeon VMAX: Espeon V evolves to Espeon VMAX that's all. Espeon VMAX however...pretty good for some support and that attack isn't as cool as it seems. Most VMAXs require 2-3 energy attacks. So the average damage you'll be doing is 120-180
Gengar V+VMAX- YES!! I love this Gengar VMAX. 250+ Single strike support!! You're only 20 damage less than UrshifuVMAX but you don't have to discard all your energy. And your first attack isnt that bad either. This might see play over Eternatus specifically because of the higher damage output +Better energy acceleration.
Inteleon VMAX- This is a great card!!! For a single energy attachement you can do 140 consistently. And that ability is pretty nuts as well. I can see this being it's own stand alone deck or a partner in Rapid Strike decks.
Adventure's discovery: Damn you turn 1 no supporter rule!! This card would be great turn 1 going first! This also includes VMAX, so you can have a very easy time setting up. Still I think it may see some play considering you can grab a crobat V off of this.
All in all... These cards are really cool!! I love the mechanic of single strike and rapid strike! This allows for so much creativity and deck building post rotation(Aka once tag teams are gone) Cant wait to see what the VMAXs do