Like many others here, I use a limited number of openings.
For White (6) openings and responses to non 1.e4 e5 by black.
the Danish Gambit
and a response to the half-open defenses:
Smith Morra Gambits vs the Sicilian
Panov-Botvinnik Attack vs the Caro-Kann
Modern mainline vs the Alekhine
Mainline Mieses-Kotrc vs the Scandinavian
Exchange vs the French
Make it up as I go Attack vs everything else.
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As black if 1.e4---- e5 and accept all gambits.
1.d4---the QGA
1.f4---Fromm's Gambit.
vs anything else, the trusty Make-it-up-as-I-go Defense.
So that would be (9) openings that I know something about and use.
My three mains:
Nimzo-Larsen for White,
Sicilian for Black,
Nimzo/Bogo Indian for Black.
Also:
A Queen's Indian type of setup against London,
a Semi-Slav setup against hypermodern White openings,
and a Colle-Zukertort against hypermodern Black defenses ...
So ... 6 I guess? Not counting the "rely on general principles" when the opponent is playing random stuff.