Get Active Cluster Node - Two slightly different methods, depending on SQL version.

Get Basic Cluster Information - Active node plus a list of all nodes and shared drives available.

Cluster Failover Testing - A list of tests to perform to ensure that failover will actually work when needed.

Cluster Troubleshooting - Some common problems and where to start.

Get Availability Group Details - get availability group details - names, nodes, IPs etc

Get Availability Group Secondaries - Get a list of databases on a server that are operating as Availability Group Secondaries

Managing SQL Agent Jobs in an Availability Group - Managing SQL Agent jobs on an Availability Group failover