Former Adventurer
You left adventuring for your own reasons and set up to what you long considered to be an honest profession. Whether it was tending bar at a tavern, mending broken tools at a blacksmith, or some other work, it has kept you in relatively good shape, even though you may be constantly looking over your shoulder.
What caused you to quit a life of adventure? What drags you back? What are you leaving behind?
One set of tools granted by this background, common clothes.
Though in many ways you have slipped from the heights of your prowess, moments of greatness do occur. Once per long rest, when you roll a critical on an attack or to cast a spell, you add an expertise die to your next saving throw or attack roll, whichever comes first.
Some are able to wed their lives as adventurers to that of a humble shopkeep or other mundane profession, and their businesses often benefit from their reputations. When you gain a stronghold and its type matches what you did for a profession outside of adventuring, you gain an additional follower above and beyond what the stronghold would normally award. As people connect your name with the business, it can support you at one higher level of lifestyle than you otherwise would be.