Personally I'd keep the more modern PSUs in use since they have more safety functionality than really old stuff, but the late ATX 1.0 spec stuff with a big 5v rail or -5v rail still present is worth keeping operational 😀 I've retrofit TFX power supplies into a bunch of my old computers since they're small, extremely cheap and brackets can be easily made with the 3d printer.
The move has put a lot of retro electronics type stuff on hold but now that's done I've got this big USB-PD powerbank and some USB-C / USB-PD trigger chips that make the USB-PD power bank (or any USB Power Delivery PSU) give out 9/12/15/20v. I have enough DC-powered devices that keeping the original PSU in use for everything just isn't feasible, these trigger chips are very cheap and so I can easily make different PSU cables for different laptop types - here's one that fits Fujitsu / Sony / Panasonic plug laptops and gives out 15v.
My mini bench PSU just got upgraded with a similar chip so it can run from the powerbank too, that's one of my first 3d prints from about 5 years ago now. It had a hole in the back because it was someone else's model and I did not know CAD back then. Now the gap is filled with a tidy looking USB-C port 😀
The battery itself is nothing too fancy but with 185Wh of capacity it can run a laptop with no mains power nearby for quite a while.
Oh also, the Fujitsu Lifebook B110 here is such a cool mini laptop, it has ESS 1869 ISA-bus audio that's initialised by the BIOS so it's working very nicely for DOS games.
Edit: Huh, these PD trigger cables also work nicely with my Anker USB charger from a few years back that has USB-C with 35W PD on it 😀 The nice thing about the particular type I've got is that they're plug rather than receptable so it doesn't even use up a USB-C cable, those introduce another failure point too, some USB-C cables aren't happy doing 20V power delivery.