good job. It's worth more in functional order than for the gold present. highly doubful there's even a gram of gold in total.
clearly old industrial gear.

well the ports on the 3rd card say "measure" and "relais" so it's probably a custom I/O control card for some industrial equipment as that's what most SBCs are usually used in.

OK cool. I'll just forget about it. If it was a bus controller for a passive backplane I'd have tried it out but if I can't find out I'll just build something around the other 2 cards and get a rack of some sort.

That last card is a 'one-of-a-kind' custom something card which I agree is to measure 'something' 😀 The number of bodges on that properly made card are a good clue, it's likely there's very few of those in existence and they're each quite useless without the custom software and hardware it was designed to be used with. I found a similar Xilinx fpga equipped 16-bit ISA card in a scrap lot similar to yours, no hits at all for the boards markings.

The VGA card can probably be used as a regular ISA graphics card, but it might need the card's BIOS reflashed since I've found that usually these things are set up to display on the no longer present LCD screen.

Nice work in getting the SBC board working 😀
Now that the systems those are in are being scrapped, I've seen them come up in gold scrap lots as well recently. I got a really nice Advantech PCA-6751 (Pentium 166MMX with Chips VGA) out of a similar lot a few months ago.

Cool. This ones a pentium 133. I'll just keep the other board a curiosity. And build a machine with the other bits.