I don't have any specific models for you (well, maybe only a few). As rasz_pl and VivienM noted, PSUs were sort of "invisible" / not talked about or paid much attention to back then. So looking for specific models will likely not yield too much while skipping a great deal of OEM and even some non-OEM PSUs that were decent.
I used to post pictures of a lot of PSUs on badcaps.net some years back (and still do or plant to... though I rarely get to it.) But if you dig back through my posts there and or of other people who had similar interests in reviving older PSUs, you might find good info and some model numbers to go off of there.
Otherwise, as other have said, just look for manufacturers that made decent PSUs back then. Here are a few I know were present in the 2000's and earlier:
- Astec. I don't know if they sold stand-alone units to the public, buy they were widely-used in OEM systems and always rock-solid built with quality Japanese capacitors (though many did use Nichicon heavily, and there's a good chance you might run into the PR and PL series, the former of which are known from leaking from the bottom and destroying PSU traces.)
- Lite-On (or LiteOn). Again, I don't know if they sold stand-alone units to the public, but they were large OEM for Dell and HP. Their Pentium 3 -era units often had Japanese-only caps and are pretty much bullet-proof.
- Mitac. Another OEM PSU manufacturer from "back in the day". Well-built and typically used either Japanese-only or a mix of Japanese and Taiwanese caps on the secondary.
- Delta. Another old and very-well-regarded OEM for big-name PCs. Like Mitac, their old PSUs used a mic of Japanese and Taiwanese caps. Otherwise 100% solid PSUs. Can always count on a Delta to meet the spec on its label.
- Newton Power. IIRC, this is either a division or sister company of Delta... or at least closely related in some way. So same applies as to Delta.
- HiPro (later renamed themselves to Chicony or Chicony Power). Same as above 3 entries, though they rarely (if ever?) used Japanese caps on the secondary side. Nonetheless, many of these still work fine with their original caps, as HiPro always did a superb job with the cooling and managing stress on the caps. So they are very solid PSUs, too.
- Bestec: another OEM for HP, Compaq, eMachines, and a few others. Similar to HiPro, they are rather solid PSUs, but rarely had good quality (Japanese) caps on the secondary side. *AND* AVOID the Bestec ATX-250-12E. That's a PSU from mid-2000's, but it's infamously known as THE motherboard killer (due to 5VSB circuit overshooting / over-volting and killing the SIO and/or SB on the MB.) Also, it's possible that Bestec designs prior to the above model may also contain the same dangerous 5VSB circuit. So model's from the early or prior to the 2000's are to be avoided, unless completely recapped (recapping fixes the 5VSB problem.)
- Sparkle Power / Fortron Source / FSP Group. OEM'ed units for quite a few big-name PC brands and also sold under their own name. They are solid PSU's, but typically need a recap at this point. AFAIK, some "less-known" companies also bought units from then and then sold it as their own / under their own name. One older brand like this that I recall is "PowerTech".
- Enlight (IIRC, that's the name). Both OEMed for PC manufacturers and sold to other companies to be rebranded or included with the case. I haven't gotten any through my bench, though I've seen a few on badcaps forums, and they appear to be pretty decent units.
- Macron or Macron Power. This brand is more of a "generic", as they didn't go out of their way to sell stand-alone PSUs too much. At the same time, they also weren't an OEM supplier for brand-name PCs. Rather, they often were "came-with-the-case" PSU or some obscure company bought their PSUs and slapped their own label on them. Overall, they are pretty decent quality PSUs. However, they 100% need a recap at this point, since pretty much all of them used really garbage cap brands. Generally, you'll find Macron PSUs under the name of... well, Macron or Macron Power. The MPT-301 model was quite popular in the early 2000's. Usually, you can tell a PSU's manufacturer by the UL certification number, if it has one (CAUTION: if a PSU doesn't list a UL number on its label, it may be a generic POS). For Macron, it's E199529
- Deer / Allied / L&C (collectively built by SolyTech). Like Macron Power above, these were often "sold-with-the-case" type of PSUs (typically that was Deer) or sold individually as "generic" power boxes (Allied and L&C). From the latter (Allied and L&C), Allied was similarly-built or better than Deer in some cases. Meanwhile, L&C was right at the bottom of the barrel. All in all, I DO NOT recommend these PSUs to anyone, except to people who are into rebuilding PSUs and/or someone that knows how to recap a PSUs. In particular, Deer and Allied PSUs typically only need a recap and maybe a few "minor" tweaks to become fairly decent retro PSUs. But L&C - those actually require extensive knowledge of the inner workings of an SMPS if it is desired to turn these into something useful. And Deer actually do have a legit UL number: E203196. Meanwhile, L&C PSUs usually don't because... well, they could probably never pass any of UL safety / Hi-Pot tests. Thus no UL number for these.
In short: Allied and Deer - OK after a recap, but recommended for lower-power systems (i.e. PII or P3). L&C - AVOID!!! (Unless you like to play with PSUs.)
There's probably a lot more that I didn't mention. However, the above are what I have came across myself.
Obviously, there's quite a few other good brands, like Enermax, Zippy, Ethasys, PC P&C, AcBel Polytech, Chenbro, and Seasonic.
Then there was another "famous" brand of PSUs from back in the day: Leadman / PowMax. But it was famous for all of the WRONG reasons 🤣. Particularly, they were often "copied" designs from other PSUs, but just not done very well. Not uncommon to see one blow up. 100% AVOID THIS BRAND.
