I have for sale a GVP I/O Extender and a CyberVision 64 (with pass-through Flicker-fixer) that would go nicely in your A3000. Also, I have available 8 stock zip chips, 2.04 and 3.0 ROMs, a replacement stock SCSI chip, and a Ramsey upgrade chip (this requires another chip replaced concurrently, but can't think of which one off the bat). Lastly, I have a Dataflyer Ram expansion that can add 8 megs Ram (I should be able to populate that with 8 megs and test it for you.) I also have some Ram sticks, but I'm trying to populate all the boards I have fully before selling off single sticks. Everything mentioned will work in the 3000.
Don't have an accelerator to offer; that's what went out on the 3000 and originally mothballed it.
I also have two external floppy drives if you're looking for less floppy-swapping action.