I think one of the more useful ones not mentioned would be idempotency. That is, ensure for any given message, processing it multiple times will be at least tol

I think one of the more useful ones not mentioned would be idempotency. That is, ensure for any given message, processing it multiple times will be at least tolerated, but ideally yield identical state. This eases so many complexities of dealing with failures (it's always safe to to retry, even if the receipient may have processed your first attempt), coherency, etc etc.