I've never seen a chart. There are some basic rules however that will give you a good idea of how dark a steel will etch, based on alloy content and hardness.
Nickel content is the deciding factor in how much a steel will resist the etchant and retain its polished brightness (there are other alloys that will do the same, however they are rarely used in modern times). The higher the nickel content, the more it will resist the etch, and the brighter it will appear. Pure nickel will be the brightest of all, followed by 203e, then 15n20 and L6.
There are specific alloys that will cause the steel to appear darker, the two I am aware of are chromium and manganese, and there are likely others I am not aware of. It is safe to say that the higher the manganese content, the darker the steel will be. This is one of the reasons Aldo's 1084 is popular, it has a fairly high manganese content so gives great contrast mixed with 15n20... it is also simple to heat-treat, welds easily, and makes a fine blade. Aldo's 1095 or W2, on the other hand, will not be as dark when mixed with 15n20 because both steels have a very low manganese content. Steels with chrome also tend to etch darker, but I have not experimented much in this direction.
Now one could theoretically make a multi-tone damascus using many types of steel in a billet, but this can also lead to problems. I once had the bright idea to make damascus using 1095, 5160, and 15n20. One would expect three distinct shades when the steel was etched. Unfortunately, the two blades I made from the mix tore themselves apart in the quench due to the drastically different hardenabilities of the steels. The more comparable the steels are to one another, the better the odds are of making a viable mix, this is another reason we use 1084 and 15n20... the only real difference between the two is the nickel content. Chromium and manganese both have a large effect on the hardenability of the steel, so mixing a very high manganese steel with one with a very low content is just asking for a tragic ending in the quench. Carbon will migrate and equalize throughout the billet, but chromium and manganese will not....