Of course!! This is something that gets brushed over a lot in music spaces to the point where I have been unable to find literally anything online like what I'm creating, at least not on the English or Spanish parts of the internet. This is probably going to take a lot of effort and is likely to never be exhaustive but I think it's worth it in the end.

Thanks for adding some additional thoughts to the list. I also came across a source about Gibson using oysters for their guitars, but as I mentioned the source was nearly 20 years old and I have no idea if this is still the case. From what I've read, Taylor only switched to synthetic materials a few years ago so anything could have happened. If I'm unable to find any recent sources I will just try and contact the manufacturer themselves. If they are unable to help I'll just put them down as undetermined/inconclusive for now.

Thanks for helping and adding some names. If possible do you have a source on Sigma, if not I will try and find one within the next couple of days. Yes, I believe classical guitars are generally the main offender when it comes to animal parts in guitars, similarly it appears that a lot of the classical-type violins are the ones that still use horsehair.

I am including all of the proof and links in the spreadsheet I'm drawing up. This post is just an appeal for additional info for now.

Of course! Always happy to try and help people make more ethical choices, especially when it comes to things like musical instruments where the issue is so muddy.