If a good value for less than $1,000.00 appeals to you, Hana makes a mono cartridge;
https://www.hanacartridges.com/products/hana-sl-mono-mk-ii
More costly options to look into would be from EMT and Miyajima.
Mono cartridge recommendations for Dual 1229Q
I'm planning to make my Dual 1229Q dedicated for mono playback. What are some recommended contemporary mono cartridges that will work well with this TT's arm? (Note: I'm good with going somewhat budget on this, so long as I can get 80-90% of the performance of the pricier mono carts.)