I have brewed many developers in the past just for fun (D-23, D-76 divided, Neofin Blue, Caffenol...) but today I'm settled with the following developers:
PC-TEA: my multipurpose developer
510-PYRO: I use it mainly to develop large format sheets film
Parodinal: for stand development when I need compensating
and Caffenol-C-H to develop 400 iso rolls pushed @ 800.
PC-TEA/510-PYRO and (pa)rodinal have an outstanding shelf life. This is also a reason why I love them so much!