Google Wave chaos collaboration brilliance vs the conventional Google+ was killed prior to Google+.
Free GMail/limited apps for Domains. This was killed for new domains in 2012, and merging/destroying through failed merge via single sign on to YouTube/other services. Generic services weren't a good substitute for 'owning' a name via domain.
XMPP was killed by G+ Hangouts in 2013.
Reader, of course.
It seemed like G+ killed anything that it could, in any fractional way, be deemed a substitute for. The memory I have of these products were of functional things. The memory I have of G+ is a large whitespace screen with an avatar and exceptionally mediocre half solutions. G+ was not fun, it wasn't social, it wasn't even average.