PC/Apple/etc. Cards Worth Keeping/Storing

I am trying to decide what to do with a bunch of 16-bit ISA IDE/Floppy controller, etc. cards. Is there still a use for them, or should I just add (most of) them to the (rapidly growing) scrap reclaim box? What about 8-bit and/or 16-bit ethernet cards, no-name 8-bit serial/parallel cards, older style floppy disk cables that still support the 5 1/4" floppy drives? Maybe a better question; are they any cards worth saving? I am keeping all the disk controller cards, memory expansion cards, and any specialized cards. Are they any Apple IIx cards worth saving? My general rule there has been that if I have the docs, they are worth saving. I have boxes of this stuff spread around and am looking for some guidelines on what might be worth keeping! I am getting to the point that anything past about 1984 or so goes.