You have three options as I see it:
1) Add a Zorro II GVP HC+8 card if you desire an additional maximum of 8MB of slower 16-bit memory and a dma scsi interface.
2) Find, if you're lucky, a Zorro III FastlaneZ3 ram/scsi controller card. Most versions will allow you to add up to 64mb of 32-bit ram in matched 30-pin simms. You'll need at least SuperBuster9 an better yet version 11 to use the fast dma scsi-2 controller.
3) Buy a cpu slot accelerator with built in scsi controller. There are/were basically three manufacturers of such processor replacement cards: GVP/GVP-m, Phase5/DCE, and ACT/Apollo. The GVP-m and Phase5 manufactured cards are probably the best, being the most reliable, using standard 72-pin simms up to 128mb and fast dma scsi controllers. The earlier GVP boards use special 64-pin simms and optional scsi controller; the Apollo scsi implementation is a bit flaky. Quality of the DCE cards varies from okay to bad.