The Shiptheory Print Client uses the drivers installed on your computer to communicate with your printer, so if you can print to it normally then it will work with the Print Client.
In terms of specific examples that are compatible with Macs, both the Zebra 420d and Citizen CL-S521 are popular examples which our customers tend to use.
When buying a printer, it is best to double check the OS compatibility before you buy.
If you require any help with this, or have another question. Please get into contact with our support team.