You could also learn the tetrachords.
They are little known, and handy as hell, mainly used by jazz sages. There are four, but there are a possible six.
They are basically a set of four notes: a root note, its fourth and any other two notes in between.
I think if you look further into theory, you can find other forms of tetrachords, but I haven't looked that far.
All the above each have a second and a third note, the other two, for which I couldn't find names, would be like the Persian and Blues or something.
I've learnt them to the point I've forgotten about them. It's better to look for them in scales if you want to use them, but if you know them by sound, they are handy for creating melodies.
1 2 b3 4
1 2 3 4
1 b2 b3 5
1 b2 3 4
1 b2 bb3 4
1 #2 3 4