draw.io - Online diagramming application
Elevate - Elevate is an award-winning brain training tool designed to build communication and analytical skills.
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.
Peak - Peak is the automated way to keep track of what everyone is working on.
PlantUML - PlantUML is an open-source tool that uses simple textual descriptions to draw UML diagrams.
Brain Workshop - Brain Workshop is a open-source version of the dual n-back brain training exercise.