Color genetics work about the same for all chickens (although silkies only come in certain colors, and I don't keep up with that list.)
Black, blue, and splash are often crossed with each other.
Any color that comes in a black and a blue version will often be crossed together (partridge with blue partridge, wheaten with blue wheaten, black laced red with blue laced red, black laced white with blue laced white, etc.)
Lavender (aka "self blue") and black get crossed together: the offspring will be black but split to lavender (they carry one copy of the recessive gene, but don't show it.) Those chicks can be crossed to lavenders to produce half lavender offspring, with the other half being more blacks split to lavender. [If the original "blacks" are already split to lavender, then the first generation chicks will be half lavender and half split.]
Crossing the gold and silver versions of a given color (gold laced/silver laced, gold columbian/silver columbian, etc) is usually discouraged. The daughters will match their father, while the sons will look like messy silvers and will also carry the gold gene. There will be no gold males, no matter which parent is which color; and the silvers (either gender) will usually have some amount of red or gold leakage, or yellowing in the feathers. But at least the black patterning should still be OK.
Crossing breeds with different patterns--laced, columbian, partridge, etc--will usually give messy-looking birds, and is very strongly discouraged if you want to get standard-looking colors.
In some breeds, whites are regularly crossed with blacks, in other breeds not, and I don't know which is the norm with silkies. (Genetically speaking, there are several ways to "make" a white chicken, and some work well with black while others do not.)
I don't know where to buy silkies, and I don't know which colors are popular.