So as others have mentioned, there’s a few levels to this, and I’ve explored a few of them I think. Currently on a bit of an exploration around multi-sample sample packs.
At the ground floor level the Samples from Mars collection is freaking awesome. There aren’t many total no brainers for music production, but this one of the few. I bought the Essentials collection and ran the synths through Preset Maker and while it’s a small sample of the whole collection, they are perfect for creating Ableton instruments. I think the full packs maybe come with pre-made instruments for the DAW which the Essentials doesn’t? Probably going to upgrade to the full thing at some point.
There are a couple of others that, depending on taste, also make great little instruments. I really rate Soundghost - they only have a handful of instruments, but they’re always good (mostly based around ambient/chill/lo-fi music.) Then there’s F9, who has some awesome multi-sample instruments, more around house & other commercial-ish sounding electronic gear. A lot of their stuff is multi-samples of classic gear, while the Ableton store packs can err on the side of esoteric at times. I’d put the 2 above in a similar category to SFM, except that their collections are a lot more limited and specific to genre.
Ableton sells some add on packs too as you mentioned, and some of these are pretty decent. I’ve picked up a few of the freebies, but there’s paid stuff too - really this would be to taste.
Between those 4 you have a lot of material to work with. The one thing I would say is that, unlike Kontakt, a multisample Ableton Instrument Rack is 100% backwards compatible, so literally anything you buy/create in this department will basically always work. I think this is an underrated factor when looking at these packs. You don’t have a manager or some big software downloader, nor do you have to deal with Kontakt 6, 7, and presumabuly in the future 8 and 9 and 10 and so on. You just… load the rack. With Live 12 getting a better preset manager, it should (in theory) start to become a bit easier to integrate your 3rd party packs with Ableton’s own categorisation. I’m liking the idea of working more directly in Ableton because of the potential of these multi-sample packs.
But since you mention it, you can’t really ignore Kontakt for multi-sampled instruments. There are 2-3 levels of pricing here, ranging from dirt-cheap to astronomical. Being as Kontakt is industry standard, a lot of professionals use it and the price of some libraries reflects that. As is well documented, the dirt cheap ones usually require full Kontakt, which means getting into the NI ecosystem. If you’re a hobbyist, to me it probably makes more sense to get Komplete Standard/Ultimate and just work with what NI brings to the table, as there is a hell of a lot there without needing to go to 3rd party vendors.
If you’re going beyond NI, there are some awesome pack makers out there, though some of them can get very expensive very quickly. I couldn’t even begin to list the players in this space, but at the hobbyist level there are quite a few well known players. Think Heavyocity, Teletone Audio, Output, Soundiron, Project Sam etc, etc. Then there are some huge libraries by companies charging professional money, such as Spitfire Audio, Strezov Sampling, Audio Imperia etc.
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