There is only one flaw in the BH tier where you could get parental bond or any banned abilities. This is done through mega evolution, which is however, not banned.
Lets start with an example:
Kangaskhan with magic bounce.
Magic bounce is always handy/useful.
A set for Kangaskhan can be like Kangaskhan @ Kangaskhanite, this is whereby mega evoltion comes about, and kanga can get pbond.
so a usual set for this kanga can be like
Super fang, you know why rite? --> instantly - 75% off your current hp.
Sacred Fire --> Burns are really helpful especially against strudy shedys. Also sacred fire 50% burn rate, could get a burn twice, even if lum berry, still will burn.
ExtremeSpeed--> +2 Priority should kill with STAB against enemy with only 25% hp left?
Drain Punch--> Recovery is always useful.
This is pretty much broken, as pbond is banned, anyways, if opponent has trace for no apparent reason, random opponent with pbond?
Here is the set for those who want it:
Kangaskhan (F) @ Kangaskhanite
Ability: Magic Bounce
EVs: 252 HP / 252 Atk / 252 Def / 252 SAtk / 252 SDef / 252 Spd
Adamant Nature
- Sacred Fire
- Super Fang
- ExtremeSpeed
- Drain Punch
Its not very commonly seen as it is outclassed by other pokes in BH. So my thoughts on mega kanga below:
I personally think mega Kangaskhan even with pbond should be in the B+ rank, as it can be easily countered, like superpower or other stuff like boomburst... also mega Kangaskhan doesnt have the greatest of speeds. I personally have swept with this poke before, so i think it should be in the B+ rank.
Will post again about another broken mega evo in BH soon.