I wanted something easy to place and remove so I can get the bed on and off. My Ender 3 has a removable bed and was sent with paper clips. I didn't like them. It is hard to get off. And if the hot end runs into them, they are too strong and don't move. My clips are just strong enough to hold the bed, but not so strong as to stop the stepper motors moving the hot end.
No special printing needed. I used PETG. Figured the PLA will soften or melt.