I find the names and huge variety of 'gravel' tyres really interesting, especially now that I have a bike that is capable of being ridden as a 'gravel bike' (Cannondale Slate) although I do use it for a bit of single track, and light MTB'ish stuff as well.
It's currently fitted with the G-One All Round, and whilst fairly new, will be used until worn out.
The surfaces that I see are road (to get to some of the dirt tracks), smooth hard packed and sometimes rocky single track (up & downhill) that is mostly dry or damp but not muddy, or proper gravel/dirt back roads. So the G-Ones at the moment, suit me fine.
I was shown a link to a test in Granfondo e-magazine,
there they tested 10 tyres (in 700C) to come up with their recommendations. Makes for interesting reading (lotsa details !!).
The tyres they tested were
Challenge Gravel Grinder - 38C
Compass Barlow Pass - 38C
Donnelly X'PLOR MSO - 40C
Maxxis Rambler - 40C
Maxxis Ravager - 40C
Panaracer Gravel King - 43C
Schwalbe G-One Bite Evo Microskin - 40C
Schwalbe G-One Allround Evo V-Guard - 40C
WTB Resolute - 42C
WTB Riddler - 37C
Really interesting reading that and seeing even more names and brands in this thread. Having 650B wheels, makes some of the coices a bit more limited, but still really interesting