This Left Click icon is made in Material Design style developed by Google. This style is based on extremely simplified shapes, thin two-pixel lines, and is optimized for 24x24 px. Unlike other vector icon packs that have merely hundreds of icons, this icon pack contains 5,500 icons, all in the same style and quality.
It's a computer mouse. The clicker on the left side of the mouse has been shaded with dots, and extending from the direction of the left clicker are two waves. The waves get bigger the further they go outward.