I use built-ins for KiCad when avail, or make manually using DSes otherwise. (Schematic and footprint). You can also download from certain websites, but I've found those are hit+miss; overall had an easier experience doing by hand, even though that sounds bad. I'll usually start by C+Ping a similar one. I have a separate KiCad library with its own Git repo for footprints, and one for schematic parts.