there are several pokemon that can not be found as misdreavus, suicune, giratina, reshiram, zekrom, palkia, heatran, victini, tornadus, thundurus, flabebe, inkay, binacle, helioptile, tyrunt, dedenne, goomy, noibat, comfey, passimian, sandygast , turtonator, drampa, jangmo-o.
Kirlia can not evolve into gardevoir.
It is also necessary that some Pokémon are a little easier to find or increase the probability of finding it.
It would also be good to use mega-evolution in the fight.
You also need more ultra beast and it would be great to reduce the costs of the evolutionary items.