SnapEDA (www.snapeda.com) is a free, online parts library for circuit board design. I started this because of my frustrations designing PCBs and getting derailed making symbols & footprints from scratch, and testing dubious SPICE models.
The library currently includes PCB footprints, schematic symbols, and 3D models that export to EAGLE, KiCad, Altium, Cadence OrCAD & Allegro, Mentor PADS, & Pulsonix. We plan to expand to other formats and types of content moving forward.
Our library is free and will always be free to support designers.
By the way, we have an API if anyone has ideas on how they can use our data in their projects! Please contact me for more info at email@example.com.
We are currently running a Beta program for our Premium version. If interested, send me your username and I'll upgrade your account during the Beta. The new version includes better workflows, 3D models, and more. firstname.lastname@example.org