Baroquemusic.it is a terrific resource! There are a few solo pieces for bassoon (including two Vivaldi concertos—RV501 and RV487—and the Boismortier concerto in D) and considerable chamber music with prominent bassoon parts (e.g. Zelenka trio sonata #5, ZWV 181). A special favorite of mine is Biagio Marini’s Affetti Musicali (1617) which features great early Baroque writing for bassoon. The scores are immaculate, many produced directly from manuscripts. MIDI files are included. We used the MIDI files for a concerto in Garageband to easily create a handy accompaniment (muting the solo track and adjusting the tempo) for practicing. The editions are also indexed and linked through IMSLP.