Got a used HP Probook laptop. Just needs a new drive. HP specs say it has an m.2 2280 slot. So that’s what I ordered. Guess I needed to look closer.
edit: Thanks for all the info, guys. Different types of keys are explained here. Gonna have to look for a sketchy no-name brand.
Another thing to watch out for is single-sided vs double-sided. Many laptops have flush mounted m.2 slots that won’t fit an SSD with chips on both sides of the board.