I found this web site recently that teaches piano accompaniment. http://users.wireweb.net/green/pianolessons.htm
I selected option 2 which cost $20.00 U.S. and he emails links to PDF files with music notation and links to MIDI files. There must be over 100 different piano accompaniment patterns. Pop, rock, blues, country, jazz, praise & worship, jewish. Phew!! Well if quantity is what you want, you would get your money's worth. I will let you know if the quality is good.
Starkeeper