Route 1 can spawn a few mon so you won't have to worry about too Many different mons spawning.
Route 5 spawns some rare and exotic mons only if you are playing the Sword version like Farfetch'd.
Route 3- the best, Rolycolies and Gossifleur spawn like crazy there, so you can keep your catch combo.
Glimwood Tangle have a variety of rare psychics and they look good if they are shiny too.
The wild areas:
East West Axewell
Lake of Outrage
Brilliant Pokemon also helps the chance of Shiny Spawning.
After successfully capturing a Pokemon, more of these Pokemon will spawn for a short time.
I hoped I've helped!