TheNounProject Incredible resource with thousands of free icons.
AnimatIcons Animated GIF icons, some are free. Few but very nice.
Icons8 More than a million free icon sets.
FontAwesome Very popular icon library and toolkit.
Material.io/Resources/Icons Icons from Google.
SimpleIcons Downloadable SVG icons for popular brands.
IonIcons Very neat open-source premium icon set.
StreamlineIcons Service for quickly customizing 140,000+ graphics. (it looks freemium).
TablerIcons 1400+ Free customizable SVG icons, ready to paste into your HTML.
LordIcon Paid icon set, but it has some cool free icons.
KeyIcons Clean icon set is ideal for web, mobile, and other uses. Figma and Sketch formats.
Zwicon 500+ icons are organized neatly in categories.
Tilda.cc/Free-Icons Several free icon sets for landing pages, organized in categories.
IconSVG.xyz Easily modifiable and ready to use, SVG icons in HTML.
Twemoji Twitter Twitter’s 3200+ free Unicode, Open Source Emoji.
JoyPixels Several emoji icon sets. Licensing varies.
Ikonate Conveniently customizable SVG icons.
Icons.Pixsellz Material Design icons in Sketch and Figma formats.
UseAnimations Animated icons (SVG & json) for applications or webpages.
RemixIcon Free neutral-style system icons for designers and developers.
Akveo.Github.io/Eva-icons 480+ Open Source icons for typical tasks and things. SVG & PNG.
FlatIcon Massive vector, sticker, and icon library with millions of items.
FeatherIcons 280+ beautiful open-source simple icons.
EverIcons 460+ free sleek icons organized in categories.
IconBros 490+ collections with 23,000+ free icons.
BoxIcons 1600+ Open Source icons for designers and developers.
IconMonstr 310+ collections with 4,700+ free icons.
PotlabIcons Not very big but have a clean free icon set ideal for web, mobile, and other uses.
DigitalNomadIcons Stunning digital nomad lifestyle icon set
Polaris-Icons.Shopify E-commerce Icon library from Shopify.
InvisionApp.com/Inside-Design/Design-Resources/Essentials-Icon-Pack A bundle with the most-used icons. Consistent style, multiple formats.