Johto Route 38 - Bulbapedia, the community-driven Pokémon encyclopedia

Johto Route 30 - Bulbapedia, the community-driven Pokémon encyclopedia

Pokemon: Everything In The Johto Region Changed In HeartGold & SoulSilver

Johto Route 30: Arrangement ◓ Pokémon HeartGold & SoulSilver

Johto Route 37 - Bulbapedia, the community-driven Pokémon encyclopedia

Pokemon HeartGold and SoulSilver Walkthrough - PokeDream

Route 30 - Pokemon Gold, Silver and Crystal Guide - IGN

3 Ways to Capture All Three Legendary Dogs in Pokémon SoulSilver and HeartGold

Pokéarth - Johto - Route 44

All Heart Scale Locations in Pokemon Heartgold/Soulsilver

Here is a map I made with the location and info for all catchable Pokemon in Sun and Moon : r/pokemon