Tools to Acquire Audio
This is only for stuff related to ripping your own audio!
Sites
https://lucida.to - This is an in-browser audio ripper that pulls music down from the various major streaming sites (Spotify, Deezer, etc). You can pull down individual tracks or whole albums, in a variety of audio qualities, and you can use Lucida’s built-in search by either artist or album to find what you want, or provide a direct link. Will be higher quality than ripping from YouTube (unless you select for a lower quality ofc). Please note that at the moment Lucida has been having reliability issues (which is deeply unfortunate because it's great when it works! haha)
https://spotifydown.com/ - This is an in-browser audio ripper that pulls music down specifically/only from Spotify. I’ve added this as a Lucida alternative as this is the downloader you’ll most often see people mention when it comes to Spotify, and I’ve seen it suggested many times in the Yoto subreddit. I prefer Lucida as Spotify Down is not searchable–you must provide the link yourself–but it is a lot simpler than Lucida to use and may be less intimidating. I have also not yet confirmed if this is pulling the audio directly from Spotify, or content-matching the songs to another site (usually YouTube) and ripping them that way, which would result in an inferior audio quality and the possibility for downloading the wrong songs (though I suspect that is the case), so please double-check MP3s you rip with this to make sure the songs are correct until I have a chance to give it a better look! Please note this website does have ads! So please consider using an ad-blocker or being careful with your clicks.
https://cnvmp3.com/ - An in-browser audio-ripper for YouTube video audio. I haven't tested it yet myself, but I’ve seen it recommended. It has no ads. I probably wouldn't use this for commercial music due to the aforementioned potential quality issues (though I don't think there'd be much of an audible difference) and the fact that it doesn't support playlists (I've got a program that does in the software tools section), but it would be good for content specifically from YouTube creators or book-reads/audiobooks people have uploaded.
https://podcasttomp3.com - Downloads episodes of podcasts–useful if you want only certain episodes, or you need earlier episodes than Yoto’s built-in podcast interface is able to grab. I haven’t had a chance to test this much yet, but it seems promising! It does appear to have a limitation of how far back it can grab episodes for long podcasts, so it may not be suitable for podcasts that have multiple years worth of episodes.
Software
Mediahuman YouTube to MP3 Downloader - Free (and ad-free!) software that takes individual or playlist links from YouTube (and some other websites) and downloads them as MP3s. Quickest and easiest option I’ve found for YouTube ripping, since it does whole playlists and can be run in the background. However, despite listing support for Spotify I have noticed that it tries to match Spotify content to YouTube and pull it down from there, so at the moment I can’t recommend it for use with Spotify until I figure out if there’s a way to get it to use it as a direct source (as it's my understanding that YouTube audio is typically lower quality than that of music streaming).
Video Download Helper - A browser add-on that will rip any streaming video or audio from pretty much any webpage. If you have some streaming content and don’t know what to download it with, this is always worth a try. Can be used as an in-browser solution to pull from YouTube* (not recommended as it requires conversion), but its main point of interest for Yoto MYOs is the ability to rip the MP3s of audiobooks you’ve rented from Libby if they are playing in your browser. I have not yet tested this with subscription video streaming services (eg Netlifx, Disney+), Audible, etc, as I don’t have the subscriptions, so if anyone gives it a go I’d love to know the results!
*Chrome blocks YouTube video downloading, so this feature only works in other browsers.
Mediahuman Audio Converter - If you already have audio but it’s in the wrong format, this will quickly batch-convert most audio formats into MP3 so you can use them with Yoto (I have even successfully used it for the fussy M4B format).
Audacity - Free audio editing software. If you need to edit some audio down into chapters/smaller pieces, this is what to use, but there is a learning curve.
Soulseek - This is where I get most of my files. That said, I wouldn’t recommend this for anyone without a moderate level of familiarity with computers/piracy. If you have an understanding of torrents/torrenting, then this is appropriate for you. If you don’t then you’ll probably have a better time with YouTube ripping and such. Soulseek is a peer-to-peer file-sharing network/client, aimed largely at sharing music but I have found a fair amount of audiobook content on here as well. It only shows the files of people who are currently online, so searching at different hours/days will give different results. Please note that in order to use Soulseek you also have to be willing to share your own files (feel free to share files that you’ve gotten from me, that’s the whole idea).
TLDR really great and simple way to get audio, but only if you have the pre-existing skills to make it simple.