They should all function pretty much the same. Giving 512KB or ram and a realtime clock. The one with the button battery is probably more useful these days as the battery can be swapped out easily and won't leak, whereas the yellow card's battery is very prone to leaking and can damage the internals of the A500 if it does.

The one with the metal shield is probably a Commodore made one. They always seemed to encase their trapdoor expansions in metal shielding, whereas most others didn't and just supplied the naked board.

The only different can sometimes be how the A500 sees the ram. Some trapdoor expansions will show the extra 512KB ram as fast ram, others will see it as slow ram (but still report it in the Workbench as fast ram), and some will be seen as Chip ram and give the A500 1MB chip ram (if it has the newer fatter Agnus chip that supports more chip ram). Only way to tell is to try each card in an A500.

There were a lot of different trapdoor memory expansions produced for the A500 in lots of different sizes and designs. They are however quite rare these days to fine so they are sort after by Amiga users.