Just a taste and you'll be hooked: an order of Limitless Non Player Characters vol.1 will be in your future.

I plugged Beazel the Alchemist into a shop in a small town my players were exploring in our 5e campaign and he was an instant hit. I'm planning on an encounter with Ceaseus the Shipwright soon. I am now the proud owner of the aforementioned Vol 1 for help with populating our campaign world both deliberately and on-the-fly during our gaming sessions.

The Limitless team does a great job of giving enough mechanics and background flavor to make the NPC come alive with enough flexibility to allow you to plug the NPC in to most any scenario. The Further Adventure prompts are great in themselves, but also help to get the creative juices flowing for crafting your own home brew encounters.