India and Pakistan both rushed their programs back in the 40s/50s ( or maybe later I can't recall off the top of my head). Libya and South Africa were negotiated away. That leaves Israel probably from the, what, 70s or 80s? And North Korea was supported by Russia and China. I'm not sure you could consider any of those countries to be "pursuing nuclear weapons" today. Plus by that logic you'd have to throw in the US, UK, China, Soviets, and France too.

So when you sort of set aside countries from prior to, idk, 1980s ish you don't really have anyone at least publicly (to your point) pursuing nuclear weapons. However it's not just the enrichment of uranium which is tightly controlled it's also the missile technology to deliver the weapons. Keeping a nuclear program secret these days I think is quite a bit more difficult than in the past.

So when you look around today you've got Iran that we know of pursuing a nuclear program. I'm not sure anyone else is by virtue of how difficult (I think?) it would be to do so undetected. Though there are countries (Japan and Korea come to mind) who we think have the ability to scale up a program very quickly.

India and Pakistan were late 90s.

Japan and South Korea literally have 100s of American military bases on their territory. You really think they are sovereign nations who can pursue an independent nuclear program?