These IIe cards do still amazingly work in many machines!
( from wikipedia )
Host system compatibility [edit]
The card plugs into the PDS slot in many of the LC-series Macintoshes, but not all models and system software combinations are supported. Apple's Tech Info Library article #8458 lists the following models as Apple IIe Card-compatible: Color Classic, LC, LC II, III & III+; LC 475, 520, 550, 575; Quadra 605 and Performa 4XX, 52X, 55X, 56X, and 57X. However, other models that have an LC-compatible PDS slot and support 24-bit memory addressing are compatible with the Apple IIe Card but are not officially supported. Systems 7.0 through 7.5.5 support both 24- and 32-bit addressing on suitable Macintosh models. (From System 7.6 onwards, Macintosh system software does not support 24-bit addressing.) To enable 24-bit addressing on supported systems, use the Macintosh Memory control panel.