Since you are interested in Brahms: Ein deutsches Requiem op.45 [A German Requiem], here is a list of other items that you may find interesting.
Arias & Cantatas
Schola Cantorum Basiliensis / Rene Jacobs
[ Harmonia Mundi Gold / CD - released 20/May/2010 ]
Caspar Kittel (1603-1639) was a German musician who trained in Italy and returned to work at the Dresden Court, deputizing for his colleague Heinrich Schütz when the latter spent a period in Denmark.
J. S. BACH
Akademie fur Alte Musik Berlin
[ Harmonia Mundi Gold / 2 CD - released 1/Jun/2010 ]
"Trumpeter Friedemann Immer must have made at least half-a-dozen recordings of the Second Brandenburg. The present performance should rank among his strongest, though, since he negotiates with commendable security most of this challenging music...
Cello Sonata Op.47 (with Liszt - Elegies, La Lugubre Gondole, etc)
Emmanuelle Bertrand (cello) Pascal Amoyel (piano)
[ Harmonia Mundi Musique d'abord / CD - released 25/Jul/2014 ]
"intelligently played and beautifully recorded." - Gramophone February 2002
Bella madre dei fiori-Cantatas
Maria Cristina Kiehr (soprano) / Concerto Soave, Jean-Marc Aymes, director
[ Harmonia Mundi Gold / CD - released 20/Feb/2009 ]
"Three chamber cantatas, including the finest Correa nel seno amato, its opening an outpouring of rare intensity and sustained despair. Tweaking tone controls softened a tungsten edge to Kiehr voice." (BBC Music)
W. A. MOZART
London Baroque, Charles Medlam
[ Harmonia Mundi Gold / CD - released 25/Mar/2008 ]
" Nothing sounds uncharacteristic - bustle, and a sure architectonic ear are in evidence across these works written between 1772 and 1780.They are jewelled little works each in a single movement." (MusicWeb)