Mastering Precision Piecing by Sally Collins
Setting Solutions, by Sharyn Craig
The Border Workbook, by Janet Kime
Nickel Quilt books by Pat Speth - My favorite is 'more nickel quilts' I think she has an anthology with all the publications in a single volume. These are for 5" charms.
One Block Wonder by Maxine Rosenthal - one trick pony, but really fun!
Any Judy Martin book