Scales to Play Over Bm
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 Bm chord contains the notes B – D – F#. Any scale that includes every one of those 3 tones fits over it — from the root B, that means B Natural Minor, B Melodic Minor, B Harmonic Minor, B Minor Pentatonic, B Blues, B Rock 'n' Roll, B Dorian, B Phrygian, B Dorian Bebop, B Half Whole Diminished, B Gypsy Major and B Gypsy Minor. Start with the first scale listed: it is the most common choice, and the others color the same chord tones differently.
Bm is also diatonic to 3 major keys: A major (relative minor F#m), D major (relative minor Bm), G major (relative minor Em). 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.