For accurately measuring filters, small signal amplifiers in their linear range, switches and the like, then I'll use a VNA. It's the most used tool when sorting out RF circuitry, with the exception of non linear and high power stuff. If you're doing any serious design work then nothing else will do.
To measure third order intercept point of an amplifier then it's two signal generators and a spec ana. Most modern sig gens have decent modulation capability built in.
It's rare that I use an oscilloscope unless I have unwanted oscillations or want to measure something that isn't RF.
For high power amplifiers then a load pull set is very useful, but unless there's a lot of HPA work going on then you can get by without one. The overhead in setting one up means it gives no benefit.
It's handy to have a power meter and a bench DMM about, but it's not often they are needed.
If you're doing anything where noise figure is to be measured you'll need a noise source.
It's also useful to have a variety of couplers, splitters, attenuators and more adaptors and cables than you think you'll need. A decent soldering station and if you're doing anything small then a microscope. Books of Rs and Cs, boxes of Coilcraft inductors.
If you're doing PLL or synthesizer design, then a frequency counter and possibly a phase noise test set, or at least a spec ana with a phase noise capability is required.
It's very easy to spend a lot of money on decent RF kit.
The one essential you missed off your list was power supplies.