果汁导航

Simplify documentation and avoid heavy tools. Open source Visio Alternative. Commonly used for explaining your code! Mermaid is a simple markdown-like script language for generating charts from text via javascript.

Aconvert.com converts all kinds of document, ebook, image, icon, video, audio and archive files online for free.

秘塔写作猫

百度脑图，便捷的脑图编辑工具 - 控制创意，如此简单。让您在线上直接创建、保存并分享你的思路。免安装 云存储 易分享 体验舒适 功能丰富

ChartCube - 在线图表制作工具

GeoGebra - the world’s favorite, free math tools used by over 100 million students and teachers