Procore - Procore is the world's most widely used construction project management software. Easy to use, mobile platform with unlimited user licenses.
draw.io - Online diagramming application
Fieldwire - The construction app for project and task management in the field.
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.
CMiC - Cloud-based, single database PM and financials software
PlantUML - PlantUML is an open-source tool that uses simple textual descriptions to draw UML diagrams.