Pokéarth - Kanto - Route 3

Pokémon Gold & Silver vs. Pokémon HeartGold & SoulSilver: Full Comparison - Cheat Code Central

Pokemon Missing Routes? [Part 1]

Route 29 - Pokemon World Online Wiki

Johto Route 48 - Bulbapedia, the community-driven Pokémon encyclopedia

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

Pokémon Gold and Silver/Route 8 — StrategyWiki

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

Walkthrough:Pokémon HeartGold and SoulSilver (Part 4), Pokémon Wiki