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.
LibreOffice - Free office suite, open source, and compatible with .doc, .docx, .xls, .xlsx, .ppt, .pptx files. Updated regularly – download for free. Originally based on OpenOffice.org.
draw.io - Online diagramming application
WPS Office - Would you need Office Word, Excel or PowerPoint for Home, business or School? WPS.com would give you right version for you.
PlantUML - PlantUML is an open-source tool that uses simple textual descriptions to draw UML diagrams.
Asana - Asana project management is an effort to re-imagine how we work together, through modern productivity software. Fast and versatile, Asana helps individuals and groups get more done.