Amiga 3000 will accept 16 megs of fast memory on the motherboard. If you get an accelerator for the CPU slot, some of these will accept another 128 Megs (anyone have more?) DKB made a Zorro III card that would add 128 Megs per board with or without an accelerator. I forget the max number of boards possible. I think they are called DKB 3128. They are usually expensive if they can be found.
It's a terrible shame no one makes a modern ram expansion (and other functions) for Zorro III.