Champion Music

With every champion you release a theme song for them and every single one of them are amazing and really capture the champion's personality and play style. I'm still fairly new to the game all things considered(been playing for about a year an a half). I was on Soundcloud earlier Downloading all the theme songs for the champions(Which I want to thank you for sharing with us all for free <3) and saw that some of the older champions didn't have theme songs (Evelynn, Elise, Karthus, Malzahar, Shyvana, Irelia just to name a few). I was wondering if perhaps I missed the time to download them? Or is it something where that wasn't something you did back then? If it's the case of where you didn't make themes for them back then do you plan to do so in the future? Kind of like what we saw on "The Music of League Vol. 1"?