draw.io - Online diagramming application
GPS Status & Toolbox - Display your GPS and sensor data: Shows the position, number and signal strength of GPS satellites.
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.
Trail Sense - An Android app which uses your phone's sensors to assist with wilderness treks or survival situations.
PlantUML - PlantUML is an open-source tool that uses simple textual descriptions to draw UML diagrams.
iHunter Alberta - iHunter Alberta is an amazing mobile application offered by Inside Outside Studio Inc.