This depends on the key of the song you are playing! In the key of B-flat major, the E-flat major, F major, and G minor chords are often used along with the B-flat major chord.  In the key of E-flat major, it is often paired with the E-flat major chord, A-flat major chord, and C minor chord. In the F major, it is often played alongside the F major chord, C major chord, and D minor chord. There are other keys in which the B-flat major chord is used, so these are just examples of some of the most common instances.