L-6, D-2, CPM3V
Actually, the list is longer, and one of these steels I personally don't use (L-6), but I want to!
Why those three?
D-2. Edge holding rivaling any other tool steel, almost stainless, tough, and 'relatively' easy to work....at least in comparison to 420V. Not the king in edge holding, or the best for a very large blade, but very consistent results in heat treating, and my customers keep coming back for it even if it isn't high tech.
CPM3V. Tough like 5160, edge holding (in my experience) on par with D-2, and 'some' corrosion resistance due to its chromium and vanadium content. It does not rust like A-2 or 5160, at least in drier climates. It also works very easily annealed, similar to 5160, so you don't use up your budget in grinding belts getting to something that resembles a knife! It shows promise, even though it hasn't been out for very long.
L-6. Very flexible in how it can be hardened and at what hardness you can use it. Its tough enough to be left full hard Rc63-64, for a thin, small utility knife, but with a bainite temper and flame hardened edge it is also almost indestructible. Howard clark had some big chef's knives of L-6 at the last show I was at that were ground impossibly thin, (tapering from 1/10" at the spine) and showed a temper line in the polish. Sitting alongside them was a similar thickness test blade that had been bent completely around in a 'U' shape without the edge cracking or the blade shattering.
YMMV
madpoet