So your best bet if you want a genuine keyboard would be to search for an M2519 keyboard. That is the one that came with the Plus. An M0110, which came with the 128 and 512, will also work.

As far as other options go tinkerBOBYPH has an etsy store where he sells various adapters. I have this one: https://www.etsy.com/listing/1824990541/tinkerboy-ps2-keyboard-to-mac-converter?gpla=1&gao=1&

It works well.
Thank you for the reply. Where would be a good place to shop for the original KB and Mouse?? The prices on EBay are crazy. The items on ETSY look good though.