D Major is a warm Key, joyous and boisterous without being edgy or overbearing.
Brahms wrote a symphony in D Major that is one of the sunniest of all symphonies.
Vivaldi wrote his famous piece Spring from the Four Seasons in this Key, and Handel chose it for his famous Hallelujah Chorus in the Messiah.
B Minor is the relative Minor of D Major because it shares the same Key signature. In my opinion the Key of B Minor has a more penetrating, focused character than other Minor Keys.
As for famous pieces in this Key, Bach’s great Mass in B Minor comes to mind, as does Chopin’s last sonata, his Sonata in B Minor Op. 58.