I believe the best option would be a TM8E Magtape control, which is a 4 board set: M8321, M8322, M8323, and M8327. Good luck finding one! There was also the TR02, which was a Posibus thing, but it is quite odd, and unlikely to be very useful.
Similarly, the RK8E (M7104, M7105, and M7106) is the RK05 Disk Interface.
You may also need an expansion chassis, depending on how big your 8/A backplane is.