Sprint reports and burndown charts live under a project's Reports section, tracking how work completed against what was planned for a given sprint. Velocity charts track that trend across multiple sprints.
Cumulative flow diagrams show how issues are distributed across statuses over time, useful for spotting where work is piling up in a workflow.
Dashboards are built from gadgets you add and arrange yourself, and a lot of the more useful ones are backed by a saved JQL filter rather than a fixed report type, so the gadget shows exactly the subset of issues you care about.