Trichord and Tetrachord Subsets of the Diminished Scale
Yesterday I posted some initial thoughts on the "whole tone dominants" -- those altered dominant chords that are subsets of the whole tone scale. The obvious other thing to do, particularly with my current obsession with Scriabin, is to look at the "octatonic dominants" that come out of the half-whole (or whole-half) diminished scale. Caveat: this post is a bit of "primary research" -- not very exciting as at stands, but with potentially useful applications.
I'll take it as read that you know this scale contains some common seventh chords -- the dominant (1 3 5 b7), dominant 7b5 (1 3 b5 b7), minor seventh (1 b3 5 b7), half-diminished (1 b3 b5 b7) and diminished (1 b3 b5 bb7) chords. So it also contains the three triads underlying them (major, minor and diminished). Those you already know, although you might like to practice finding them within the diminished scale itself.
Note that dominant 7b5 is in this collection and also the whole-tone dominants collection, so it could be seen as a bridge between the two.
I'm also interested in pitch collections that I wouldn't usually "see" in this scale because they're less familiar in themselves or as subsets of familiar chords. It so happens that these all contain a semitone. For a functional application you can consider the chord given to be a C7 and resolve to F (major or minor), but more fun can be had by playing long strings of these and their whole-tone relatives to creat long, unresolved dominant textures in the manner of Debussy, Bartok and the like.
Because of the symmetry of the scale, any of these shapes can be transposed by one or more minor thirds and remains in the scale (but in most cases becomes a different chord).