UML Designer - UML Designer provides a set of common diagrams to work with UML 2.5 models.
Thunkable - Powerful but easy to use, drag-and-drop mobile app builder.
Diagramo - Diagramo is an online flowchart software - diagrams (create, edit and share)
MIT App Inventor - App Inventor is a cloud-based tool, which means you can create apps for phones or tablets right in your web browser.
ARIS Express - ARIS Express is based on the proven ARIS methodology and industry standards.
Bubble.io - Building tech is slow and expensive. Bubble is the most powerful no-code platform for creating digital products.