Are there any stitches that are specific to knitting/crocheting only?
Not completely.
You can get the same effects or the same journey of the thread/string while using other methods to construct the fabric.
Knot tyers often use the basic knitting stitches when making fenders out of rope, but constructed completely different.

And when working with string or rope you can copy almost all knitting and crochetting stitches. But in most cases it is not worth the work.
Specially crochetting is hard to copy and not worth the effort.

When doing both knitting and crochetting you will find that the stitches are unique to one or the other, and it is almost never possible to create the effect of stitches in one while doing the other.

There are a few stitches which need both knitting and crochetting. But you need both to make them, you can not make them with either one alone.

I am a creative knot tyer and do knit, crochet and other crafts. And I am good in seeing/recognizing patterns. Most people will not know about the patterns cropping up across other crafts.