Inspiring Paragon : Your creatures always have this creature’s other traits
The extra traits should not be temporary, but rather implicitly always there, as long as the avatar is alive, and as such circumvent trait gaining counters such as blackhole, and the realm trait.
It shares two, possibly three traits, always:
The avatar’s fusion trait,
The avatar’s artifact trait,
and a netherstone trait.
And it could possibly share more, if one wanted to allow it to mirror temporary traits too.
I think this would be an interesting counterpart to Regalis:
(It only gives 2/3 traits, to 5 creatures, rather than 5 to 6, but is a bit more dependable, and potentially could interact nicely with temporary traits)