Nickel and Titanium are both earlier TC wires; the earliest TC mods could sometimes only do Ni, then Nickel and Titanium, then Stainless. Now some do it all. Of the three, stainless is the most modern option and arguably the best; the range of coils available in SS and its general popularity reflect that.
I would personally recommend just going with stainless. People certainly like and use Nickel and Titanium, but SS can be vaped in both wattage and temp modes and simply has a lot of benefits over the other two. Nickel especially can be very "fiddly" and difficult to get a good vape from. If you struggle to get a satisfying vape with an SS coil in TC mode, you can always switch over to wattage for a bit.
Tons and tons and tons of
tanks have SS coils, and plenty have nickel and Titanium coils as well. Actually, I'd say the majority of subtanks have at least one TC coil option now. A few do not. It would be helpful if you were a little more specific about what you're looking for in a tank besides some kind of TC coils. Clouds? Flavor? Capacity? Something else?