Here's my attempt to put Zygarde and Necrozma on the level of Fug:
Necrozma:
>Neuroforce now gives a hidden x2 multiplier to Psychic, similar to Water Bubble
>Neuroforce keeps the effects of Prismatic Armor
>Neuroforce also has the effects of Beast Boost
>Ultra Bursting gives +1 to all stats similar to the boss fight
>Speed is bumped up to 131 because 129 is not prime and it allows it to outspeed Mega Gengar
Zygarde:
>ability changes to Aura Break after changing to Complete Forme
>fully heals after Power Construct activates
>Core Enforcer is like a Freeze Dry for Dark and Fairy
>Core Enforcer doesn't have that weird "has to go before Zygarde in order to have its ability suppressed" clause
>can be turned into Complete Forme outside of battle, allowing it to start the battle Complete at the cost of the above mentioned free full restore
>now learns Recover so it doesn't have to rely on Rest
