Biggest ones missing IMHO:
Justice
Luck
Sea/Ocean
Love/Passion
Darkness
Frost/Winter
Then there are unlimited possibilities, especially considering variations e.g. a Sun domain is not necessary the same as a Light domain, and there could be both an Undeath and a (good) Death/Dead domain that work differently than the DMG Death domain.
Among the many:
Arts/Beauty
Greed
Agriculture
Travel
Fear
Chaos
Forests
Disease
Mountains
Destruction
Strength
Moon
Crafts
Wisdom
Freedom
Vengeance
Hunting
Trade
Mischief
Joy
...
I'm not sure some of these are really omissions as much as too narrow.
Take a domain like tempest: it can represent sky gods, storm gods, destruction gods, etc. It's pretty broad. How many can joy represent? Wisdom?
Moreso, what is the difference between trickery and mischief? What does forests bring that nature doesn't?
I'd rather see only a handful of new domains than dozens of "dragon below" specific domains.
Any new domain has to be broad enough to support an entire subclass in flavor and mechanics.