DbSchema - DbSchema - Visual Database Design & Management Tool
draw.io - Online diagramming application
SAP PowerDesigner - SAP PowerDesigner: Enterprise Architecture tools for digital transformation success
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.
pgModeler - Open source data modeling tool designed for PostgreSQL. No more DDL commands written by hand. Let pgModeler do the job for you!
PlantUML - PlantUML is an open-source tool that uses simple textual descriptions to draw UML diagrams.