Take some time to go to your local gun shows, flea markets and less reputable stop&robs and see what they are selling. I’ve found covert non-metal neck knives, switchblade lighters, .22 revolvers that fold up like a large pocket knife, etc.
Many of these items can be picked up very cheap. I bought the switchblade lighter for $2 at a gas station. I keep these items handy for use as displays in training and court. If I go up against a defendant’s lawyer on a suppression hearing out of a Terry stop I have plenty of ‘ammo’ to counter any claims that what I felt couldn’t be a weapon, according to my training and experience.
It will also keep you updated on what kind of pipes, etc. your local dopers are buying. Things are easier to spot when you have seen them before.