Export
of destination AS-Path is supported in the sFlow extended_gateway structure.
As a consumer of sFlow, [as well as NetFlow, IPFIX, etc.] I haven’t run into the use of this option in production, FWIW.
In addition to BGP, there are a number of MPLS, tunnel encap/decap etc. sFlow extended structures.
Some of these options are encountered fairly frequently; others, not so much. As you note, they have different applications.
Also optical interface metrics, dropped packet notifications, and more:
Dropped traffic is pretty much universally supported and utilized, in my experience. Other options, again, not very often.
Some flow telemetry implementations support packet export, to one degree or another; and, of course, there’s PSAMP, which utilizes IPFIX as its transport. AFAIK, these aren’t observed very often in production, to date.