1. The majority of digital voice modes are on Ham UHF.
2. Ham UHF has a satellite sub band for FM operation, and some birds have linear translators for SSB, which can accommodate multiples stations at a time.
3. Fast scan TV.
4. Some have high power EME, moon bounce, stations using digital or analog modes.
5. World wide linked repeaters, using different types of digital voice modes.
There’s more but the above is what comes to mind.