Is there any recource for a compilation of privacy focused alternatives?
Whether it be third party clients (like we used to have Infinity and Apollo and what not for reddit) or separate services, like ddg or firefox for web, kbin or lemmy instead of reddit.
right now looking for snapchat alternatives, preferably a different client if at all possible.
Do not forget https://www.privacyguides.org/ . You are in the "Privacy Guides" community after all and this link is in the side bar. This is a general answer. Maybe does not list anything for your specific client question though.
Another one I like is https://alternativeto.net/. Not specifically privacy, but gets an alternative list for almost anything, and there are various search filters too.
I think it's unlikely you'll find another Snapchat client, haven't used it for years but I read they were banning accounts that were using 3rd party clients
Your not going to find third party clients like the way Infinity is implemented, instead your only option is modded clients. This doesn't have anything that improves your privacy from Snapchat itself unless you are talking about the spoof location but you could just not give Snapchat your location in the first place. Never used it, but Mobilism and Rockmods are trusted in the piracy community so its worth a shot if it fits your needs.
For snapchat, it would be hard to create alternative client, because it has no API that lets you send or view recordings, so it would require reverse engineering and/or checking its communication with the server. If you want alternative for snap, you'd need to invite your friends there, and there the problem begins.