Garuda: Just came back from SYD with first leg SYD-DPS operated by GA, KL marketed. As some of you know from one of the threads I've published, I've been unable to select seats in advance(* it's apparently impossible on a GA operated, KL marketed flight).
At check-in, I've been assigned 21K on A330-300, which is a bulkhead and extra-legroom seat, and it's normally paid. I actually discovered it's a *published* benefit of all ST Elite Plus members:

https://www.garuda-indonesia.com/id/...selection.page

I enjoyed flying with GA for the first time. Entertainment system was a little old on the A330, but food was very good for Y standards and the crew did a great service during all flight.

Alitalia: I've been upgraded on dod to short-haul C a couple of times in the past, both on AZ marketed and AZ ticket (LIN-LCY), and on KL marketed/KL ticket/AZ operated (LIN-AMS, when the partnership was still ongoing though).

Delta: Listed for upgrade in EC / F on many internal routes (I guess it's a published benefit though). Been successful only once from Y to F (I guess it was ATL-BOS in 2014).