I am looking for a reasonable cartridge for a modified AR ES-1 turntable

I only have one. No hum.
Besides they couldn't create hum if they tried.  
Perhaps rephrase.

I had an AR ES-1 and used it with a Grado cartridge. That was at least 15 years ago.
Yes, the motor field did induce hum into the cartridge. I bought some mu-metal foil and put it under the platter and was able to get around that. I regret, I can’t give further details, it was so long ago, and all that gear is long since gone from my possession.

Thank you for your comments on the Grado cartridge used with AR-ES-1

I own a modified AR-ES1  The Shure V-15 type V-MR has been the cart and stylus of choice for many, many people (inc myself) for a long tome.  Find a NOS or used excellent and go from there.  They can be rebuilt or re tipped