Complete Minimalistic Opening Repertoire
Do you want to minimize time spent on remembering gazillions of opening moves, while still playing sound openings? Then I suggest that you play the Kings Indian Attack (KIA) with white against any black defence (I bet you can even premove the first 7 moves!) Start with 1.Nf3 to stop 1...e5.
These three openings result in similar structures where you need to be familiar with ideas rather than remembering specific moves. So, it's basically one system against everything! The structures leads to slow dynamic, and often unbalanced positions, with a decisive nature.
This will be good enough at least up to candidate master level (ELO ~1900). Above that level it should be assisted with more options.