V-I isn’t the only option. Dominant chords can go lots of other places besides I.
A dominant chord, say F7, will generally be a V-type chord, setting up a I-type chord. F7 –> Bb. (key at end of progression: Bb)
But that’s not the only option. There are also these:
Tritone Substitution: resolves down by half-step, so F7 –> E. (key at end of progression: E)
Back Door ii-V: resolves upwards by whole-step, so F7 –> G. (key at end of progression: G)
Deceptive Cadence: resolves upwards to the relative minor key, so F7 –> Gmi. (key at end of progression: Gmi)
Circle of Fifths Chain ii-V: resolves downward by fifth to another ii-V, so F7 –> Bbmi7 / Eb7) (key at end of progression: Ab)
Chromatic Chain ii-V: transposes a previous ii-V downward by half-step so Cmi7 / F7 –> Bmi7 / E7 (key at end of progression: A)
Circle of Fifths Insert ii-V: extends a progression by transposing upwards by whole step, so Cmi7 / F7 –> Dmi7 / G7 (key at end of progression: C)
Modal Shift ii-V Sequence: continues a progression through keys by changing modality of chord, so Cmi7 / F7 –> Fmi7 / Bb7. (key at end of progression: Eb)
By my count, that is eight different keys that the same F7 chord can easily move into. In addition to spicing up the reharmonization of a song, you can also use this in composition to move to different places. In Stevie Wonder’s recent “Can We Fix Our Nation’s Broken Heart” he uses the following chord sequence for his A section.
||: G / / / | Bmi7 / / / | C / / / | F7 / / / :||
The first time he reaches the F7, it is a back door V chord back to the G (home key). The second time, he follows its innate destination to Bb, giving a modulation to a distant key while feeling very smooth harmonically.
What other ways can you think of to reapply a dominant chord besides as a simple V chord? The more ways you can use it, the more places you can take your music!