1. Blue scale. It consists of the notes of the major scale but with additional pitches as well - lowered 3rd, raised 4th (or lowered 5th) and lowered 7th scale degrees.
2. Altered scale. In major, the ascending altered scale has additional raised 2nd and 4th scale degree and the descending scale - lowered 6th and 2nd scale degrees. In minor, the ascending altered scale consists of additional raised 4th and 7th scale degrees and the descending scale - lowered 4th and 2nd scale degrees.
3. Altered intervals. These are the augmented, double augmented, diminished, and double diminished intervals that consist of at least one raised or lowered scale degrees of the altered major or minor scale. In major: lowered 2nd, raised 2nd and raised 4th, and lowered 6th scale degrees. In minor: lowered 2nd, lowered 4th, raised 4th, and raised 7th scale degrees. Altered intervals are very useful in building altered chords.
4. Diminished triads. They consist of two juxtaposed minor thirds. Between the outer notes they have diminished 5th. In natural major, they are built from the 7th scale degree and in the harmonic major (with lowered 6th) - from the 2nd scale degree. In natural minor they are built from the 2nd scale degree and in harmonic minor (with raised 7th) - from the raised 7th scale degree.
5. Seventh chord of the 7th scale degree. In natural major it consist of three juxtaposed thirds (minor 3rd, minor 3rd, and major 3rd). Between the outer notes there is an interval of the minor 7th. Between the three lower notes - diminished triad. In harmonic major and harmonic minor all thirds are minor and the 7th is diminished.
6. Seventh chord of the 2nd scale degree. In natural major, it consist of minor 3rd, major 3rd, and minor 3rd. Between the outer notes there is an interval of the minor 7th. Between the three lower notes there is a minor triad. In natural minor and harmonic major the structure of the chord is the same as in No. 5. More about seventh chords - in my new Seventh Chord Training.
7. Dominant ninth chord. This is the most commonly found five note chord. In natural major, it is built from the 5th scale degree and has 4 consecutive thirds - major third, minor third, minor third, and major third. In other words, it is a Dominant seventh chord plus a major 3rd. The interval between the outer notes is major ninth (major 2nd plus an octave). In harmonic minor, the top third is minor and the ninth is minor. In four part harmony this chord is used incomplete - without the fifth (the middle note).
If you want to advance in your understanding of music, you can take advantage of the above terms and put them into your bag of tricks while writing and playing them in different keys and from different pitches. No matter if your goals are only to discover them in the pieces that you play or to use them in your own improvisations and compositions, I have no doubt you will find them extremely useful.