All over the place. There’s one in my wallet. I don’t always use picks but I hate looking for one when I want one. I leave them scattered around. In my cases too. Gig I’d keep a couple in my pocket. Used to do the tape on mic stand but now I don’t use them enough to mess with that.
I keep a holder in my bag/briefcase, and a couple picks in my wallet. It's frustrating when you find yourself in a shop or some other place with a guitar you want to try but don't have a pick, and cool looking guitars have a way of turning up when you least expect it.
Always some in my wallet. Even wallets I use occasionally have picks in them.
I recently came across a small leather pouch perfect for 3 or 4 picks.
Every gig bag - picks. Amp bags - picks. 3 bags with Allen keys & picks.
I make my own from credit cards & ice cream lids.