The best source of fingerings I've found is a book called
"Handy Manual Fingering Charts."
It's by Clarence V. Hendrickson and published by Carl Fischer.
The J.W. Pepper Catalog Number is 257584
It's pocket sized and only costs about six dollars.
I've purchased at least four copies,
all of which have wandered out of my room.
So I made this web page. It's bookmarked on my class room
computer so students can look up the fingerings themselves.
I think they remember better that way.
Most of the fingering charts are linked off site but a few are here.
If you'd like to add a link, or submit a correction, or if you
have better low brass fingerings, please send me an email.
Horn in F and Bb
Bass Trombone (f attachment)