You can also use VSTSynthFont (1.096 / 2.096) - VST instrument as the default, that will load any sf2/gig GM or load a different one for each track.

http://www.synthfont.com/soundfonts.html
https://musescore.org/en/node/94941
https://musescore.org/en/node/103046

As Mario said Sforzando is great and many free sfz's you can download, and some in here also: http://www.pgmusic.com/forums/ubbthreads.php?ubb=postlist&Board=75&page=1

Also Biab Win More Audio & Midi Tracks