Some very popular designs for custom keychain include:
Monogram or initials
A custom monogram or set of initials is a classic keychain design. You can have the letters engraved, embossed, stamped or painted on the keychain.
Photo
Adding a photo to a custom keychain makes it personal and meaningful. You can use iron-on photos, apply photos with decoupage medium or have photos engraved or printed on the keychain.
Charms or pendants
Adding decorative charms, pendants or trinkets to a keychain gives it eye-catching style. Things like little metal or gemstone charms, toy car charms, fingernail clippers, mini tools, etc.
Geometric shapes
Simple geometric shapes like circles, squares, triangles, hexagons or stars make for an elegant custom keychain design. The shapes can be cut out, etched or painted on the keychain.
Text
If you want to incorporate inspiring words or a meaningful phrase on your keychain, custom text is always an option. The text can be engraved, embossed, stenciled or painted on the keychain.
Symbol
Personal symbols, icons or logos that are meaningful to you can make for a unique custom keychain design. Religious symbols, band logos, hobby symbols, etc.
Nature themes
Natural elements like leaves, feathers, seashells, bones, stones, etc. can be incorporated into custom nature-themed keychains. Use real elements or representations of the elements.
Vintage or novelty
For a fun, retro look, consider vintage-style designs or novelty designs like old-fashioned keys, spanners, pocket knives, mini flashlights, mini tape measures, etc.
Magnetic clasp
A magnetic clasp attached to the end of the keychain allows you to attach and detach the keychain with ease. This works great for custom keychains made of smooth metals like stainless steel.