This is a Resume Button icon. We've made it in iOS style, first introduced in iOS version 7 and supported in all later releases up until now (at least iOS 11). This style is based on thin two-pixel lines and is optimized for 50x50 px. Unlike other vector icon packs that have merely hundreds of icons, this icon pack contains 13,000 icons, all in the same style and quality.
This is the resume button found on many electronic devices. It has a tall thing rectangle on the left hand side. The rectangle is far taller than it is wide. On the right hand side is a triangle that is almost even on all sides but it points to the right.