I have noticed in many threads folks listing loads that just don't show in my books. I have Lees, Lyman and Hornady. If you could list other books I could be using it would be greatly appreciated. I spend hours reading, trying to learn more. This hobby is addicting and I enjoy it just as much as shooting. May be I am just an a odd ball when it comes to things like this. Between reloading and building and flying rc airplanes it keeps me busy. I love retirement.
All of the major bullet makers have good information, of course, it is limited to their products. Most have good information sections as well.
All of the powder manufacturers publish data for their powders. Some of it is in print form, some is available on the internet. Hodgdon's annual magazine usually has some good extra information but most of the powder manufacturers info is limited to load data.
The little comb bound books called Loadbooks has a compilation of data from numerous sources. These books are caliber specific.
Published loads will vary from source to source for a lot of reasons. They even vary from edition to edition from the same source. There are lots of opinions as to why, but it is what it is.
I have books from Sierra, Speer, Lyman and Hornady, including several editions from each. I have powder information from Hodgdon, Alliant (and formerly Hercules), Accurate, old IMR and Winchester pamphlets and some Ramshot data. I have been collecting load data for 30 years.
I use some Berger bullets and they are good about giving you loads for their products.
There are a couple computer programs that use some kind of formulas for calculating loads. I have Load From a Disk, the other is Quick Loads, I think. I don't trust these out of hand, but they give another data point and can be compared to other data. I would not recommend these for the novice.
There are lots of other good published data out there.
One final note, the minor bullet manufacturers tend not to have published data for their products. Some have recommendations to follow such as Berry who recommends using cast bullet data for their plated bullets.
Frequently, as you look over the various different load data, you will see for bullets of the same weight and construction, the published loads cover similar ranges. This indicates that you could substitute an alternate brand of bullet loading at the lower end of the loads and work up a new load.
It is important that it is the same weight and construction. Loads for the various green bullets are different than the loads for the lead core counter parts. ditto for the solid copper bullets.
But, be aware that there are some powders like W296 and H110 that don't play nice outside narrow charge ranges.
As good as the information is that is posted on this and other forums, always verify it from a reputable published source.
Hope this helps.