What are some alternatives?
When comparing Flaticon and Open Font Library, you can also consider the following products
Font Awesome - Font Awesome makes it easy to add vector icons and social logos to your website. And version 5 is redesigned and built from the ground up!
Fontspace - FAST and FREE downloads of over 37,000 fonts for personal or professional uses. Fonts for Pinterest projects, DIY wedding invitations, scrapbooking and web design
IcoMoon - IcoMoon is an icon management tool that is build to provide iconography.
Font Squirrel - Font Squirrel scours the internet in search of FREE, highest-quality, designer-friendly, commercial-use fonts and presents them for easy downloading. We don't have the most, but we do have the best.
IconPharm - IconPharm is a library of open source icons with recoloring and resizing tools.
Google Fonts - Making the web more beautiful, fast, and open through great typography