Since I really need wider bandwidth than the super-low-distortion ones
will give me, I'm not remembering those off the top of my head.
Well-at AUDIO, you can get distortion down in the -140dBc range for
outputs at a couple volts RMS with either the OPA627/OPA637 or the
AD797 at low gains, and the '797 also has about a 4dB noise figure for
a 50 ohm source. But for wider-band RF stuff, the OPA847 is one
candidate, if used carefully. It's not quite as good as I'd like to
see, but close.

Cheers,
Tom