Allegro

Allegro, in musical terms indicates a tempo (BPM) between about 130 and 150, a rhythm therefore quite fast, pressing, but not necessarily "Happy" in the common sense of the term.
Most of these are upbeat happy tracks, but not all of them.
The instrumentation is only strings and woodwinds in almost all the pieces, which are inspired by classical music defined in the scores precisely as "Allegro."