A few of the fast and medium speed shotgun/pistol powders are fairly narrow in their recommendations, but most of them are rather versatile. I am currently using the following with a degree of success in a variety of handgun applications: W231, W244, American Select, BE-86, and Power Pistol. In the past I have also used Red Dot, No.5, Unique, Competition, HS-6, Titegroup, and Univesal, with success across a variety of handgun cartridges.
If necessary, I could probably narrow my handgun powders down to just two, but I enjoy the versatility and benefits available from a selection of powders. Plus, I'm not going to get the results I want from eight different handgun cartridges if I limit my powder choice to two.
Though not as versatile as faster powders, Alliant 2400 is usable across a fairly wide range of the revolver cartridges, and works in the 22 Hornet as well.
I don't reload and shoot enough rifle ammo to comment on the versatility of rifle powders, except that I have used the faster ones like IMR4198 and H4895 for full power loads in some of the lower capacity rifle cartridges, and down loaded them successfully in some of the Magnums.