So as I was disassembling an old dvd player to scavenge the circuit boards so I can practice soldering, thanks to the blogs, I recognized that this little bugger resembled part of a line filter. I'm looking into it now but is it possible to use these when building a filter? They're common mode chokes?Which I'm looking into now.

   

You probably could, but it depends on its voltage and current rating, and the inductance value.
Not sure what you are building, but generally speaking, modern mini quad PDB and AIO FC these days have pretty decent power filtering built-in you don't usually need to add anything extra. Maybe a low ESR capacitor occasionally, but that's about it.