There are massive differences in film developers & techniques. You have a large topic to cover, my friend. Back in the day, film development was the most important step in getting good prints. It's also really freaking hard. If you are serious about learning about film development, then at some point you should start trying the various Pyro formulas. Pyrogallic-based developers are in a class all their own. They have been around since the bad old days--old masters (Stichen, Strand, Steglitz, etc) waxed poetically about them. I believe Ansel Adams used pyro as well but I can't remember.

Anyhow, Pyro interacts with both the silver halides AND the film gel the halides are suspended in. It 'tans' the gel in proportion to the exposure, giving it a odd yellow-green cast which can make the most wonderful prints with subtle contrast gradients people swoon over. It's totally a singular experience in film development, and by the sounds of it, you like to experiment, so give Pyro a spin. There's plenty of info about the various Pyro formulas and techniques on the web. Point google at it.

The last years of shooting film (for use to make platinum prints), I developed with a Jobo autolab using Pyro exclusively. I can't get digital negatives anywhere close in terms of local contrast and subtle luminosity (which might say as much as my incompetence with digital negative crafting as much as the strength of Pyro).

You can get premix pyro at http://www.bostick-sullivan.com/cart/home.php?cat=406

or a photographers formulary I bet.