One source of information—and knives—is the
list of knife sizes from American National Knife.
The following table, from
C. G. G. Schmidt, may also be helpful. Not listed in either source are Atlas Press jointers. Their 4-inch model 6050 takes knives that are 4" x 5/8" x 1/8". The 6-inch models 6000 and 6001 take knives that are 6" x 3/4" x 1/8".