Much like the VAX, the 6809 and 6309 have a preponderance of indirect addressing modes (in VAX parlance, "deferred"), though neither go so far as to include a VAX-like doubly-indirect mode.
To what extent were these modes useful/actually used?
I can obviously think of contrived instances where these would be a good fit, but it's difficult to determine whether these would show up in the "real world". It's worth noting that the 6809's cousin, the 68HC12, removed all but two of these indirect modes.