Usually the ones that do have seats set aside for elites don't differentiate between Elite and Elite plus... any skyteam status will get those seats. CO is the exception to this who keeps Exit rows for Gold and Plat only until OLCI opens up.

DL and NW both have elite seating which you can get with any Skyteam elite level. I don't know of any special elite seating on any of the other carriers and I've flown most of them.

Really within Skyteam the best benefit you'll get out of elite plus is lounge access when flying in Y.