RE: Miasma Sun (A version of Leaferade) (Leafeon, Espeon Prime,Houndoom Prime & Roserade)
<__< Wow...I'm such an idiot. I combined both of my decks. Wow. That was pretty dumb. Well anyways, you get the gist of it.
My Leaferade deck is:
4-4 Leafeon(2 RR, 2 MD Eevee)
3-3 Roserade
1-1 Houndoom Prime
Eeveelutions:
3 Glaceon MD #5(Snow Cloak/Speed Slide are great fun!)
2 Espeon MD(Sunlight Veil)
2 Umbreon UD(Moonlight Fang)
1 Umbreon MD(Moonlight Veil)
1 Flareon RR(with Undevelop, for type coverage)
1 Jolteon RR(which I'll probably get rid of because it's attack is insufficent 90% of the time)
That's skeleton Pokemon list of both decks. Why I combined them I have no idea, but It still serves the purpose.
Anyways, Eeveelutions is like a poor-mans Arceus. Basically the goal of it is to establish what deck you're playing against(Gyarados, LuxChomp, Charizard, DialgaChomp, etc etc) and set up the appropriate counter. If no counter exists(in the example of LuxChomp, since there's no Fighting Eeveelution) then just attack with your decks beatstick(In my case, Umbreon since it can wall both Luxray and Garchomp). The key is to run plenty of recovery. Cards like Pokemon Rescue/BTS are especially useful since if you lose an Eeveelution, you'll desperately need the Eevee back since you're limited to only 4. You can Manz rescue an Eevee, and BTS whatever Eeveelution you need, then attach energy.
Like I previously mentioned, your main enemy is low hp, and medicore attacks when you're not facing weakness.
Lucario GL can help with this, but just be aware that unless you get the needed KO, you'll surely be KO'd next turn.