Father is silver tabby, mother is solid blue. Colors that are definitely possible:
Silver tabby, like the father.
Colors that may be possible depending on what recessives the father carries:
Brown tabby (if father is not homozygous silver)
Black smoke, if father carries solid (or solid black, if father is not homozygous silver)
Blue silver tabby, if father carries dilute (or blue tabby, if father is not homozygous silver)
Blue smoke, if father carries both solid and dilute (or solid blue, if father is not homozygous silver)
If the father does carry any of these recessives, each kitten will have a 50% chance of being the recessive color. So, if the father carries solid, you would expect about half the kittens to be solid. If the father carries dilute, you would expect about half the kittens to be dilute. If father is not homozygous silver, about half of the tabbies would be brown tabby, etc.