Consessions

Has anyone had luck asking for concessions from sellers? I'm curious how many sellers/developers are paying closing costs, transfer taxes (for new dev), common charges/maintenance..etc. Also, have you heard of any other incentives? What about sponsor notes to help with financing or free storage/parking? Not interested in gimmicks like vacations and cars, just real value adds. I'm back on the sidelines (just renewed by lease!) until things shake out but still going to open houses. I just want to be able to identify a good deal if I happen to come by one that isn't solely based on price. If sellers paying all closing costs is now the norm, I don't want to take it into consideration in my analysis.