What amounts are refundable if I return my plates to the DMV?
Are you wanting to transfer the remaining registration credit to another vehicle that you need to register?
I wasn't wanting to transfer the credit that way.  I was not aware that I could, but, since you said that it is possible to transfer the remaining registration credit to another vehicle, I might wait as I am about to purchase my husband a new car.
When you surrender your vehicle plates to the DMV, you may be eligible to transfer the remaining registration credit to another vehicle you want to register, or get a refund for the registration fee.  You get a refund or registration transfer credit for your vehicle plate fee, title certificate fee and any other fee or tax that you paid when you registered the vehicle.