Here's my design for a handle that fits Southord-brand lock picks. The rough outline was done in Fusion360, with some finishing done in TinkerCAD.

I printed the handle in Wood PLA on a Flashforge Artemis; here are my settings:

Layer height: 0.10 mm Extruder temp: 210C Bed temp: 70C 100% infill 5mm raft

If you print it upright so that the slot for the pick is vertical, the filament seems to be able to bridge the gap at the top just fine.

I'm including both right and left handed versions (simply flipped), as well as versions with and without holes for push-in nuts. For these nuts, I used a soldering iron to melt them into the holes, then I used grub screws to help hold the pick in place. I also used a dremel to make a little divot on the pick under each grub screw for extra hold.

Check out this page for more information about using push-in nuts with 3D prints: https://markforged.com/resources/blog/embedding-nuts-3d-printing

Message me with any questions!