heracross has some potential in expanded, use evolve to butterfree for free instant evoltuion, combined with mew or marshadow, cover some weakneses.
The pontential of miltank is also good, 60x moo-moo milks in your hand, 240 damage, knockout most gx-ex in one attack with a 1 prize attacker. Use order pads, trainer mails,skyla, or reserved tickets to increase chances? and try to get it out. expanded this has better pontential, use double colorless with mew or mew-ex, and or marshadow, but requiring some energy acceleration like max elixer? disruption cards like judge, and N has a potential to ruin the strategy, so more research should be done before making this deck.
i only see unown missing and hand being a useful win condition, damage is not viable.
tyranitar might be more useful in expanded, energy acceleration like you would for a normal darkrai deck, use brigette first turn, dark patch,rare candy, ultra balls and tapu lele,battle compressors.
lusamine prism star not useful, unless your using a full ultra beast deck, like with naganadel, in this case it gives you a chance of winning. however it does fuel unowns missing win conditon.
Lost march only natu and jumpluff, useful to summon hoppip, because skipbloom automatically sends it self to the lost zone fueling to search for jumpluf, which is a 1-off attacker, sad it has 70hp(might have to use rare candy in case of recovery problems. lost mixer might be required to thin out pokemon you have in your hand to loss zone,
in expanded better cards can be used, mew and marshadow can be used with battle compressors, can be combined with unown missing win condition. trumpbeak should be in a lost march deck, as it can instantly send itself to the lost march without being on the field, and potentially disrupting a potential supporter draw.
without prism stars, this might not be viable.
faba is basically a souped up version of xerosic, sends 1 special energy,tool, or stadium to the lost zone, no chance of recovery, useful against zoroark decks.