Terminus
If I was a wizard this wouldn't be happening to me
Twice. Once on my original copy of Emerald, and once again with SM/USUM.
Both of those were regional pokedexes, however: Gen 7 only had a regional dex, and Gen 3 made it nearly impossible to get a complete national dex without going to IRL events or having done limited time promotions for an entirely different game console.
Both of those were regional pokedexes, however: Gen 7 only had a regional dex, and Gen 3 made it nearly impossible to get a complete national dex without going to IRL events or having done limited time promotions for an entirely different game console.