I have an Open Connect device [FTC]: what data-only plans are comparable to Verizon ?

With my postpaid verizon plan I can add a data-only device.  For $20/m a hotspot has 15g lte / unlimited 600kbps.  For $20 a tablet has unlimited lte subject to network management like their basic "unlimited" account.

What are the AT&T equivalents? prepaid is greatly preferable, but I would like information on both.