9-ring Copper Magnetic Clasp - Beadology Iowa

This is a substantial clasp.  Might be great up front.  It has an elongated magnet in the middle and "male"/"female" parts for added security.  It is 10mm wide, 55mm long, and 8mm thick.

Mother of Pearl Copper Ring

Temple 3 Loop Stitch-in Magnetic Clasp, Antiqued Copper Plate, 5 per Pack - TierraCast, Inc.

Magnetic Clasps, Base Metal - Weave Got Maille

Buy Rhodium Over Sterling Silver 9mm Round Magnetic Lock with Lobster Clasp (2.50 g) at ShopLC.

Secure bracelets, necklaces, or other jewelry and crafts with the Locking Magnetic Clasps. The simple locking system allows you to easily put on jewelry with one hand and has a strong hold, so you don't have to worry about it falling off. They work best with leather cord with a diameter smaller than 4 millimeters, but it can work with other small cording as well. These clasps come in a variety of metallic solid colors and multiple pack sizes!.

Locking Magnetic Clasp - 4mm

Findings Archives - Beadology Iowa

Bead & Button, PDF, Beadwork

Magnetic Clasp With Lobster Clasp Connector Spherical For - Temu

Magnetic Tube Clasp - Yooladesign

This clasp is easy attach with prongs already on, and the set includes a metal plating for added strength on the strap side. The magnetic closures will last and are strong. Finished in a high polished brass, these will dress up any item they are used on.

Bag Clasp Snap Set Magnetic Brass 3/4 3092-01