PCI WinModems, for all I care, can be trashed and we all can pretend they never existed. ISA NICs are also interesting, as they provide an easy way to add a boot ROM like XT-IDE to bypass BIOS limitations, besides allowing networking on 286/386 PCs. I also find that even the cheapest ISA NICs usually have packet drivers with low memory footprint and work with just about anything. PCI NICs are keepers if they are based on Intel chips or other good performing ones - but I wouldn't go out of my way to preserve Realtek PCI NICs. ISA modems serve little practical purpose, but maybe there are some games where a modem is the only way to multiplay?

I have a small cache of ISA Etherlink III (3C-509B) adapters I got from my school who doesn't have any ISA machines anymore.

As far as modems go I hold on to anything US Robotics.

ISA and EISA network cards are usable, VLB network cards are collectable.

Modems for the most part are useless to most people, some externals are collectable (exotic brands from the BBS days).

I categorically recycle them.

For anything considered useless, check if it has removable components. Some old modems and network cards have socketed EPROMs or Flash chips which can be erased and reused elsewhere. These chips would almost certainly be too small to use for a motherboard BIOS, but they can be useful for other things like video cards or whatever.
Many old EPROMs are valued in various retro-electronics communities because they're useful but long out of production. For example, old arcade machines use tons of EPROMs and frequently need bad ones replaced.
Old car ECMs will have an EPROM, and people who modify the programming like to have extra chips.
Old game consoles sometimes use an EPROM in them somewhere. I once used a salvaged 4KB EPROM from a modem to hold a modified BIOS for an Atari console. People have also sometimes made modified game cartridges that use EPROMs, or sometimes using Flash chips.

Modems can be useful if you need fax. There is software for sending and receiving fax via modem and, as far as I know, there are still orgainsations that favor fax/printed correspondence and disregard e-mail.

Yup, I got tons of those sitting around here in boxes.
I've just never bothered to toss any of them as I thought they might be useful someday and because I really am not that savvy when it comes to networking (as long as it works, then all is fine to me), but if I'd sort them then I'd particularly keep the ones that are either recognized by Windows or are in another way easier to work with.
I also tended to keep the physically smaller cards as they are easier for airflowmanagement.

Only other cards I always kept are 100MBit ISA NICs, though I think I only have a single one and I've somewhat understood that this isn't especially useful for speedier networking, but it won't set your entire network back to 10MBit.

And modems...I never could think of a way to make those things useful, but as I had some spare room and a leftover box I just tossed them all in there 🤣.

Tetrium wrote:

Only other cards I always kept are 100MBit ISA NICs, though I think I only have a single one and I've somewhat understood that this isn't especially useful for speedier networking, but it won't set your entire network back to 10MBit.

Unless you have a really old and crappy 100Mbit hub, pluging in a 10baseT NIC will not slow your network down to 10Mbit. Even the old 100Mbit hubs I had before switches had an internal bridge to keep the 10 and 100 collision domains separate. A proper switch will have no issue with this.

I got one 3Com Fast EtherLink PCI 3C595-TX that I consider collectible being one of the earlier 100mbps cards. It looks like the Fast EtherLink ISA 3C515-TX uses the same chipset supported by some kind of bridge chip.

Anyone here who have tested the performance of 100mbps ISA cards?

I have one or two 10/100MB ISA NICs but have not tested them. The ISA bus is the limiting factor anyway (16 bit ISA is max 15.9 MB/sec for the whole BUS). Put in some wait states, other cards, and other overhead and the speed drops like a rock.