So classic tones in a regular SG. Knowing your amp would help but we can work with this.
My top pick, although it's also one of the most expensive options, is a set of pickups from
The Creamery. They're actually not quite as expensive as Bare Knuckles, as they're a lesser-known brand, but if anything their quality and attention to detail is second to none. They are still more expensive than your usualy Seymour Duncans or DiMarzios and since they're made in the UK postage/shipping can be high. It's not a big operation so they really do put endless care into every pickup and every customer gets their full attention. In fact saying "their" is a bit wrong as it's mostly just one guy doing everything himself, one at a time, only to order. I recently bought a couple of sets as the Bare Knuckles I've had didn't impress me and I'm tired of the same old Seymour Duncans and DiMarzios and I have to say the Creamery pickups have blown 'em all away. I hope they get more attention because they really deserve to be heard.
Anyhoo, they make a couple of pickups that would suit you. I can only really talk about the ones I've actually used though, so:
Alnico 4 '57 model: by far the best PAF copy I've found. I've played guitars with real 50s PAFs before and this 57 model seems to have all the same character that those did. He also makes the 59 which is a slightly hotter version, not tried that one myself but I'd expect it to be on par. You've got the choice of alnico 2, 4 and 5 magnets. I went for the 4 in the bridge but that's in a Firebird. For an SG I'd maybe consider a 4 in the neck and a 5 in the bridge.
Humbucker sized P-90: unlike the Phat Cat and the Bluesbucker and the Gibson P-94, this one does actually sound like a P-90. It's certainly a slightly hotter P-90 kind of tone, but it's got the P-90 response all the same. I'm using it in the neck of a Firebird and it's brilliantly crisp; if you fancy some really old school blues tones, that would be a good way to go.
Humbucker-sized Wide Range pickup: Probably my new favourite pickup. Again, I've played guitars with real Wide Range pickups (not the recent Fender reissue which is just a regular humbucker in an oversized cover) and again, these pickups nail that vibe and response perfectly. I'm seriously thinking of putting them in every guitar I own. They've got the really articulate string separation of a single coil but none of the harshness. Alternatively you could say they've got all the power and tone of a humbucker but without any mud whatsoever. They're a tiny bit brighter than the 57 model and they are a lot clearer, though they're not quite as bright as the hum-sized P-90. Definitely a great choice for the neck at least.
He also makes humbuckers with Filteron and single coil voicings. Neither of which I've tried but all indications point towards them being great. They should both be good in the neck position if you wanted a really classic, much brighter tone.
If you don't want to spend quite so much, there are a few options. SD Seth Lovers are great classic neck pickups, though they don't balance well in the bridge. A SD Pearly Gates has a bit more power and bite to it which makes it a great bridge pickup for blues or a near-perfect neck pickup for any kind of classic rock, depends how much gain you use and the exact nature of your playing. '59s may be a bit on the bright side but if your amp happens to have quite a thick or dark tone (e.g. Orange or Vox) then the 59 would balance that out well. A DiMarzio Bluesbucker is an extremely unbalanced pickup that has a ton about halfway between a P-90 and a regular low-output humbucker, though it does use ceramic magnets so the thinner strings can get a little bit harsh so that's definitely only something you'd want to put in the neck position. I've found a DM PAF Pro with the alnico 5 maget swapped for an alnico 2 magnet is a great blues and classic rock pickup although it uses black hex pole pieces so it won't look traditional and you cna't get covers for them, could be a problem.
My top picks for classic tones on a standard SG:
#1 Creamery alnico 4 57 bridge, hum-sized Wide Range neck
#2 SD Pearly Gates bridge, Seth Lover neck
#3 SD 59 bridge, Pearly Gates neck
