Tonearm for Zephyr Mk3

12g / 10uM isn't especially low compliance...
But for high mass arms the Groovemaster (for new) and the FR64S (for used) come to mind within a modest budget

You didn't say what table, what arm length, budget or any other considerations.  

I have been very pleased with a Jelco TK-850L arm, 12 inch.  I have heard other comments about TK-850 arms in different lengths.  That would seem a good option to start.  

I use my Zephyr 3 on an Origin Live Silver mk3a arm.  Sounds fantastic.