Of the seven California districts that went to Clinton and a Republican House candidate in 2016, Democrats have clearly won four. Some have called CA45 for Katie Porter over incumbent Republican Mimi Walters. It seems very likely that Democrat Gil Cisneros will defeat Young Kim for Ed Royce's CA39 seat.(She has led, but her margin has been shrinking fast.) There is even an outside chance that Democrat TJ Cox could beat incumbent David Valadao in CA21.
Nationwide, we could end up with only one or two Republicans in Clinton districts.
Over on the Senate side: If Rick Scott and Cindy "Noose Lady" Hyde-Smith both end up winning, there will be only 9 split delegations in the Senate. That would be the fewest in at least 40 years. (Unlike Pew, I count Vermont as single-party).
And finally, as Seth Masket points out, there is a strikingly similar pattern with state legislatures:
Starting in January, only one state legislature—Minnesota's—will be under split party control. In that state, Democrats took over the state house but fell one seat short of flipping the state senate last week. The last time just one state legislature was under split party control was 1914.