Scales to Play Over Gm7
Every chord is a subset of several scales: any scale that contains all of a chord's tones fits over it. Pick a chord to see the matching scales from its own root, the major keys the chord belongs to, and full fretboard diagrams for every scale on guitar.
A Gm7 chord contains the notes G – Bb – D – F. Any scale that includes every one of those 4 tones fits over it — from the root G, that means G Natural Minor, G Minor Pentatonic, G Blues, G Dorian, G Phrygian, G Dorian Bebop, G Half Whole Diminished and G Gypsy Major. They differ only in the notes between the chord tones, and that is where each scale gets its color.
Gm7 is also diatonic to 3 major keys: Bb major (relative minor Gm), Eb major (relative minor Cm), F major (relative minor Dm). In a song from one of those keys you can also solo with the key's own major scale or its relative minor pentatonic across the whole progression, not just this chord.