Man, cards like these give me all sorts of bad deck ideas...!~
Let's go in order of clunkiness, shall we~
So, the two most obvious are:
Espeon-GX
DivideGX with Dusknoir's ability will allow you to snowball fairly well.
Fairly linear, but solid strategy.
Drampa-GX
Dusclops fuels the Beserk attack, and Drampa is a good "body" to have out while you evolve.
The damage from Dusknoir's ability will help you OHKO most things with boosted Beserk~
Less viable options:
M Alakazam-EX
The damage from Dusknoir's ability will allow you to snowball well.
There's no mixing of energy types, and both will benefit from devoting your deck to evolution.
Alakazam is not that great of a body, but Duskull and Dusclops aren't terrible cards.
Zoroark BREAK
While Zoroark's Mind Jack is a little be weaker, it's a lot easier to set up.
Also, with the BREAK's attack, you're not solely reliant on their bench to do damage.
Zoroark BREAK is a lot stronger than he previously was, due to the strength of GX pokemon's attacks.
For example: Zoroark BREAK can OHKO Tapu BuluGX with Judgement, by discarding one dark energy.
Zoroark BREAK can also use a Choice Band, and rely on Altar of Moone to reduce it's retreat; instead of Float Stone.
This allows him +30 damage, yet he's not effected by Choice Band himself~
Even less viable options:
Honchkrow (Guardians Rising)
While the synergy is definitely there, I feel like it's too reliant on Dusknoir's ability.
You'd have to run Buddy-Buddy rescue in this, for sure.
Rotom (Fates Collide)
Plasmagic is a really fun attack combined with Dusclops'...
That's pretty much it.
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These are all just off the top of my head, obviously, so I'm sure I've missed some obvious combinations~
Would like to see what you guys think!
I excluded a few things like:
Tauros as a body with Dusclops attack.
NinetalesGX sniping the bench (could kill things like Rowlet, and get easy prizes).
There's also Necrozma's GX attack, after you drop some mons on the board with Dusknoir's ability... but... that's also really clunky, and relies on them playing a GX deck.
...and Garbodor, cause Garbodor.
I feel like one of the pros of this card, is... it's not an evolution ability, so we can search it with things like Wally, and still use it consistently~
But the glaring con here, is:
Your opponent can just play all their basics if they see you running this card.
With Hoopa and Shaymin rotating, there's not many basics your opponent would want to keep in hand.
Also, Quad decks have no issue with this... at all.
TL;DR
It's a cool card, with decent potential.
Interested to see what deck runs it, if at all~