Pyro Paper Planes

Thanks for the kind words. Yellow Valkyrie specifically was made using free soundfonts and some default sounds from FLStudio, specifically Squidfont (for strings), TGSF (for dulcimer and other sounds), and Ellade Percussion (for the dirty sounding drums). Those are all available here: http://soundfonts.darkesword.com/

As for the sine wave: a sine wave sound really shouldn't be hard to create, as it's the one of the purest, most basic sound you can generate. Any synthesizer plugin should allow you to create a simple sine wave. YV's sine uses a little bit of portamento to give it that pitch-scooping sound on the attack.