Well, there was the HRG (Hemispherical Resonator Gyro)which was touted
as a low cost replacement for the Litton and GM Carousel systems, but,
as you rightly comment they were beaten out by IRUs with RLGs.

The Boeing 777 has a unit called an ADIRU which comprises 3 IRUs and 3
ADCs in one unit with built in redundancy.

GPS inputs to the Flight Management Function come from MMRs (Multi-Mode
Receivers) which comprise VOR/ILS/MMR/GPS/Marker in one box. (There are
three of these per aircraft).

All very reliable compared to the 70s/80s type gear.