Figured might be helpful for some here. I’ve been compiling a list for myself and a friend, hopefully its understandable enough for anyone. The fx are ordered lowest cpu use to highest, the ranking index (for example: .06) coming from Reaper’s Performance Meter (Windows 10, 128 buffer, 44k). The numbers relative to each other is the significant conclusion. Unfortunately for some of the testing I didn’t make note of the fx I tested that were high cpu.
I use Reaper in Win10, it i really interesting, you did a great job!
Are you going to apply this to GP ? 
Thanks Hermon! Yes, seems quite likely the rankings will apply in GP as well. Reaper’s Performance Meter makes it easier and more accurate to measure cpu usage by individual plugin than any other host I have.