Folders are pretty low speed with relatively light loads, so IMO, any basic light machine oil should work. I think all these modern "space age nano lubes" are just marketing hype and more/less unnecessary.
The other thing is that a lot of people tend to over lube, and that attracts things like dust, lint, and other debris that ultimately gums up the works.
Personally, I think a good blast of compressed air is as useful as anything. Especially if your knife has phosphor bronze or nylatron bushings, which are both self lubricating. Aside from that, you shouldn't need more than a drop or so of oil. There are lots of cheap "food safe" machine oils out there, or if food safety isn't a fact, just a basic 3 in 1 or similar should be fine.
Sometimes I'll give a quick squirt of silicon spray into mine after blasting it with air, and then follow it up with another blast of air and wipe down to remove the excess, though it's rare that I oil my daily carry pivots anyway.
I'll also "over lube" when building and breaking in a slipjoint, but that's just to help flush out any dust and debris, and after break in, I'll blow the excess out again and then leave it alone.