What is the National Dex BH format?

Question

I've heard of the others but not this.

Answer 1

It's Gen 8 Balanced Hackmons but with all the Pokémon in the National Dex.

Gen 8 BH had an inbuild issue of not having behemoths such as Primal Kyogre, Arceus and especially Mega Evolutions. National Dex BH unites these uncoded Pokémon and the new Gen 8 mechanics, moves, abilities and items. It's a BH spin-off, a very popular one at that.

For more about NatDex BH, read this.