|After some extra research I found a complete list of state from different sources:
Running - The session is running one or more batches. When Multiple Active Result Sets (MARS) is enabled, a session can run multiple batches. For more information, see Using Multiple Active Result Sets (MARS).
Background - The session is running a background task, such as deadlock detection.
Rollback - The session has a transaction rollback in the process.
Pending - The session is waiting for a worker thread to become available.
Runnable - The session's task is in the runnable queue of a scheduler while waiting to get a time quantum.
Spinloop - The session's task is waiting for a spinlock to become free.
Suspended - The session is waiting for an event, such as I/O, to complete.
Sleeping - A session in the sleeping state means a client connection without an active query.
Dormant - SQL Server is resetting the session. Same as Sleeping, except Dormant also indicates that the SPID has been reset after completing an RPC event. (Replication SPIDs show "DORMANT" when waiting.)
For more information about other columns see:
SQL Server Activity Monitor
I hope it helps others.