~~ several styles available ~~
Wrist style is handy for jogging, biking, or shopping.
Cord style with swivel hook can be used lots of ways.

leather straps masculine soft leather wrist straps, with multiple key rings, in two sizes

cords with swivel hooks braided ribbon cords (Japanese Kumihimo) with swivel hooks and ribbon tassels

 
coming soon ~~~
Wallet design will handle a larger (and heavier) number of keys.
And then there will be pouches and cases with attached key rings.