Annoying vibration

Thanks ! I've had a couple folks tell me to look at EVERYTHING, motor mounts ..etc.
It is very frustrating for sure. I did put some Marvel Mystery Oil in the fuel today..,maybe that will help with the "mystery"....

So...in the last 12 months I have replaced :
Wiring harness
P-leads
Spark plugs
New Marvel Carb
I have also rebuilt :
Mags, (one twice)
Cleaned mag switch
And had my prop overhauled two weeks ago.
Completed my annual last week.
Since two weeks before the annual, I developed a moderate vibration that starts at about 1900 rpm and stays thru the higher ranges but gets a little better towards 2300rpm.
It started one day in the pattern suddenly. I don't know what is left to check, I have physically searched for any loose components..none found. During last annual AP was confident a prop overhaul would solve it but of course it has no effect other than a slick paint job.
Anyone have ideas ???