Anywhere to buy individual (HQ) instrument samples

[LDAsh]

...without needing to buy GBs of whole packs of a lot of stuff I might never use.
I'm mostly interested in low-octave samples of real instruments, because I think it's better to pitch them up than try to pitch them down.  Hopefully they would be all cleaned up and trimmed nicely, ready to use, but even if not I'd still look into it.

Free is good too.

[Saga Musix]

For orchestral samples, have a look at the BBC Philharmonia free orchestral samples: https://archive.org/details/orchestral_samples

[herodotas]

I'm mostly interested in low-octave samples of real instruments, because I think it's better to pitch them up than try to pitch them down. 

Pitched up samples playing faster, and sounding unnatural. I think, the opposite way is better.

[LPChip]

Neither works. For good samples, you need many samples to cover the whole range.

A sample that is too low will have a really short decay when high pitched and thus sounds unnatural.

A sample that is too high, sounds very sluggish on a low frequency, but it will sound better than the other way around, just not in every case. For example, a strings will work if you have a high pitched sample, and play it down on a low octave. But a trumpet will simply sound bad if its too far off its pitch.

Although a guitar has the properties of a string and thus the high pitched sound sounds okay-ish on a low octave, because it is a pluck instrument, that pluck just sounds unnatural.

But there are plenty of instruments that give you a good quality sound. Also, don't forget VST Instruments. They sometimes use syntheses to combat requiring lots of gigs of samples to create a good sounding orchestral instrument. They basically have the beginning part recorded as sample, and sustain the loop. Not the most realistic way, but usually sounds great. The same can be achieved in a Sound Font (.sf2 and .sbk) which can be played using a Sound Font player VSTi. And there are loads of instruments you can download for free in the .sf2 format.

[LDAsh]

"BBC Philharmonia free orchestral samples"

I think I saw these before, and unless I'm missing something, I can only find versions of MP3s at 96kbps, which isn't what I'd call "HQ".

"I think, the opposite way is better."

I'd like to politely disagree.  Sure the rapid vibrato and increased/lost attacks will make it sound unnatural, but from a technical point of view you won't lose any quality.  Lowering high-pitch samples might sound more natural (if the attack is tightened up) but it's a losing battle because it's impossible to retain decent enough quality, to the point where even lowering 1 octave will turn the composition into mud.

"For good samples, you need many samples to cover the whole range."

I completely agree, I currently use unique samples for every octave and do some blending on samples that approach those transitions, but the samples for the lower octaves are usually so quiet (therefore contain more 'air') and harder to clean up, while the higher octaves deafen me.  Maybe I'm tone-deaf, but I've always found that to be an artifact of digitally sampled music and I want to avoid it by making higher-pitched instruments more quiet in the samples themselves.

Ultimately, finding a library of unique uncompressed samples would be great.  I'd looked into decompiling some of the larger soundfonts I've found, but that seems a very legally fuzzy thing to do.

[Saga Musix]

I think I saw these before, and unless I'm missing something, I can only find versions of MP3s at 96kbps, which isn't what I'd call "HQ".

Strange, I recall them being around in higher quality.

[Brozilla]

Well.....

Also, don't forget VST Instruments.

VSTs are definitely among the higher quality stuff. I've sampled the EW Hollywood set a bunch of times while getting different, almost unique, flavors and flares.

Ultimately, finding a library of unique uncompressed samples would be great.  I'd looked into decompiling some of the larger soundfonts I've found, but that seems a very legally fuzzy thing to do.

FL Studio is one thing that comes to mind. Some soundfonts like JJ's French Horns, Campbell's stuff, etc. are likely usable as copyright by the author as they sampled the instruments themselves. Otherwise I think your best bet is getting a VST or sample CD.
I have junk like Sound Canvas VA (SC8820 etc.) for more retro/old SNES-like stuff and others like (Buying Soon!^tm) Komplete 11 for contemporary drafts. Though regarding legally fuzzy I'm curious about  https://www.dropbox.com/s/70bpo6525oevs5e/XR.rar?dl=0
I sampled them mono and aren't totally identifiable or do you still get in trouble?

[Alice (Midori)]

As far as orchestral/classical instruments samples go, i'd rather use SSO, or one of the newer ones, linked there as well http://sso.mattiaswestlund.net/

PS. Brozilla, SC-88 is not a junk, it's fantastic >:C
(Not saying it's gonna excell at faithful emulation of physical instruments though, but for 90s-style synthy music, classic midi modules are a pure bliss)

[Brozilla]

PS. Brozilla, SC-88 is not a junk, it's fantastic >:C
(Not saying it's gonna excell at faithful emulation of physical instruments though, but for 90s-style synthy music, classic midi modules are a pure bliss)

Well considering Nintendo still uses samples from it in modern games (e.g. SM3DWorld) I guess it says a lot.... but they also still use 32khz to this day. I called it junk 'cuz the 90's are over.

The Sound Canvas VA does blendwell with the Korg Collection products as they were released around the same time period. The Roland Drum Kits (e.g Power Set) sound great on the SNES and I even think I found some samples used in SNES games off the Korg M1/Wavestation.
From my little experiments though they do not blend well with Hollywood Orchestra and likely a lot of other "high end" orchestral software. Though when I sample the HW Strings (for the SNES) it'll beat out Roland HQ Orchestral/Roland 90's Product and Korg 90's stuff. Still have to substantially reduce the quality BUT they are rich in sound even if somewhat cheesy.