Worth the Detour Achievement in Octopath Traveler II

The Neoseeker guide has all of the side-quests pointed out during the main walkthrough, though a large portion of them will not be able to be completed when you first find them. Take a peek at their pages when you come to them, but if they require a character you haven't recruited yet, or require a trip to a high-level dungeon just move on with the story. I would suggest prioritizing quests that give XP-boosting accessories, or accessories that increase the spawn rate of rare monsters (Octopuff Pot and Cait Powder). After you complete the story, you can run through the list of side-quests by region starting HERE.