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