Mir - The purpose of Mir is to enable the development of user interfaces shells.
draw.io - Online diagramming application
Y Window System - Y Window System is a platform that allows you to improve the speed, working, and efficiency of the application in your operating system and helps you to increase the responsiveness of applications similar to any locally based app.
LucidChart - LucidChart is the missing link in online productivity suites. LucidChart allows users to create, collaborate on, and publish attractive flowcharts and other diagrams from a web browser.
DirectFB - DirectFB is a web-based platform that provides you with complete access to a software library that you can use for the acceleration of graphics, handling the input devices, and others for your Linux operating systems.
PlantUML - PlantUML is an open-source tool that uses simple textual descriptions to draw UML diagrams.