preact itself small in size (excluding some functionality from core)

Preact presents a very thinnest layer virtual dom abstraction above Real DOM, it also registers dom events to improve functionality, basic intention is to use most of the existing web functionality and less wrapping of on top of that

It also has a huge performance improvement due to its compactness. 

It even includes extra performance features like customizable update batching, optional async rendering, DOM recycling, and optimized event handling via Linked State.