I'm just wondering if anyone is aware of any library-style sites with presets for various plugins at all? I'm thinking of anything from Slate Digital to Plugin Alliance to Waves to UAD and even things like Guitar Rig, AmpliTube and so on?

I quite like deconstructing presets or using them as a starting points to get ideas on new ways of working or discovering new sounds. However, most obviously require legit plugins to access their preset libraries, thinking things like IK's ToneLab (or whatever it's called).

Therefore, just wondering if anyone is aware of any sites about with plugin presets, be it sites with presets for single plugins/manufacturers, or ones with presets for various plugins/manufacturers.

 

For everything amp sims, there is https://www.choptones.com/
https://www.choptones.com/pages/search-results-page?q=Amplitube 5
I find it expensive though

There is the IK Multimedia Amplitude community with a lot of free presets:
https://www.tone.net/amplitube