Part 5: Beat Elesa — Nimbasa City Gym, badge 4

Beat Elesa — Nimbasa City Gym, badge 4 opens 5 areas.

Where to go

1. Driftveil Drawbridge

   Wild: Ducklett 100% · Lv 23-26

2. Route 5

   Wild: Audino 85% · Lv 21-24, Gothita 30% · Lv 21-24, Minccino 30% · Lv 21-24, Solosis 30% · Lv 21-24 +5 more

3. Route 16

   Wild: Audino 85% · Lv 21-24, Gothita 30% · Lv 21-24, Minccino 30% · Lv 21-24, Solosis 30% · Lv 21-24 +4 more

4. Lostlorn Forest

   Wild: Basculin 70% · Lv 10-25, Buizel 60% · Lv 10-30, Poliwag 60% · Lv 40-70, Poliwhirl 55% · Lv 40-70 +21 more

5. Driftveil City

   Wild: Zorua Lv 25

Everything you can have caught by this checkpoint · Open the interactive guide

It also doesn't say when 5 of its areas open up, so they are listed together in the last part rather than guessed into the story.