What types of diagrams do you use for visualizing architectural solutions?

The following types of diagrams are often used for visualizing architectural solutions:

• Component Diagrams — show the structure of the system and the relationships between main modules.
• Class Diagrams — display classes, their properties, methods, and relationships.
• Sequence Diagrams — illustrate interactions between objects over time.
• Deployment Diagrams — show the physical placement of components on servers and devices.
• Data Flow Diagrams — describe the movement of data within the system.

The choice of diagram depends on the purpose: for understanding the structure — components and classes, for analyzing interactions — sequences, for infrastructure — deployment.