Brands of the World - Open source database of brands vector logos
VectorWiki - A huge repository of ~120K brand logos in SVG format for free and quick download.
LogoSear.ch - Instant search through 200K+ SVG logos from 100+ sources
Flaticon - A database of free vector icons.
BonsaiJS - A lightweight graphics library with an intuitive graphics API and an SVG renderer.
Looka - Make a logo you’ll love with Looka Logo Maker.