well, my sister told me I could visit and do some research about it, and well, they're available at mostly Japanese sites, some songs are hard to find though, I watched some on YouTube, but I have the soundtracks of Pub and GO!, Mein Gott, and Absolutely Invincible British Gentleman.
Audio.isg.si. wewe don't need to be a member and they have everything from Maru Kaite Chikyuu (even though wewe don't need that...), Hatafutte Parade, and all the Character Songs like Carrot and Sticks and With Love, From Iceland. There are also Fanmade songs.
Type in Youtube to mp3 and when wewe are at a song wewe want on youtube, just right click the box where the song is and press copy video url au something and go back to the Youtube to mp3 page and right click again and press paste then it will say convert video. Press that button and when the picture of the video shows up, press the word download and then wewe have the songs wewe want. Also, wewe might want to have Youtube and the Youtube to mp3 of different tabs. Also, sorry that it was like a summary.