In this family of stitches you make overhand knots in your thread. Sometimes you take a tiny stitch through the base fabric while you make the overhand knot; other times the knot is free-standing in the middle of a previous stitch.
This family includes one of my favorite stitches, the coral stitch. I love this stitch because it makes a strong line and is very economical of thread. I use it for curvy doodles and for a lot of drawing.
This one is called four-legged knot stitch. Here the knot just loops around the bottom thread of the X instead of going through the fabric. I might try this one again, but this time catching the fabric for a firmer stitch.
I often make little flowers at the end of my feather stitch "branches," or just mass the knots to make more solid expanses of color, as in the deviled egg below.