Well, there are probably more available than what I've managed but of the ones I am most comfortable pulling off I can list how it goes typically.
The two most frequent color requests for my clips are blue jean blue, and khaki. I believe its because both these colors provide office dwellers with some good 'urban camo' blending ability of the clip to match up to slacks they wear.
Bead blasted is by far the most frequent finish I use though.
However the scale works like this picture here shows.
What you see here is an actual piece of scrap titanium I used to show what is possible. At least from me.
I usually shy away from trying anything above 70 volts. Not because I can't do it but because for some reason, especially on the bigger pieces I don't feel the color is uniform or evenly spread out for depth and shade. Its kind of spotty to try to describe what I see after 70.
At the bottom of the voltage where titanium first begins to change is 9 volts. It looks like 6 here in the pic but its upside down.
Then at 12 it gives a darker shade of khaki, and at 15 volts even darker. 18 v is like a purple, 20 a royal blue, 25 is what I term blue jean blue, and 28 is sky blue. 30 volts is a light blue. 40 is lighter still, and 45 or there abouts (not shown) is a blue green or teal color. 50 gets a nice olive color green lighter olive but nice that I've found blends well with green canvas micarta. And usually gold or yellow for me comes at about 55 volts
60 is hard to ID. Its kind of got a hint of orange with the solution I use. .
70 is a bright almost mauve color. My enhancement of the photo may not show the colors as true as they appear in person so be aware its probably not exact.
You can see what happens after 70 but in my opinion, at least using me its needless to try anything beyond that. I rarely get uniform coverage of the material to my satisfaction even when I've etched it or bead blasted it and cleaned the heck out of the tianium before doing the anodizing.
Hope that helps.
STR