Pokémon Definitive Platinum: 3 badges — Relic (Fantina, Hearthome City)

What opens up at this point in the game, and everything you can catch by now that you couldn't before.

Newly reachable

Newly catchable (42)

ArbokAriadosAzelfCacneaCherrimDrowzeeFloatzelGirafarigHippopotasHoundourIllumiseKadabraKecleonLickitungLinooneLunatoneLuxioMewMightyenaMothimMunchlaxNidorinaNidorinoNoctowlNuzleafOctilleryPelipperPersianPorygonRaticateRemoraidShuckleSlowbroSlowpokeSolrockSuicuneSwellowTorchicVolbeatWeepinbellWobbuffetYanma