If you are looking for a way to add some pizzazz to your I-Cord, beads might be the answer you are looking for. Here are two ways to add beads to your I-Cord.
I suggest pre-stringing the beads, since I-Cord is fiddly enough as it is. Having the beads on your yarn from the start is more convenient. Also, if you are following a pattern you will place the beads as directed by the pattern. Otherwise, put them where you like, as many or as few as you like.
When you reach the point where you would like to have your bead, slide the bead up the yarn and to the needle. Bring the yarn to the front of the work, and slip the next stitch on the left needle purlwise. Take the yarn back to the back of the work, and continue knitting. (I find it helpful if I hold the bead in place with my thumbnail at this point)
Repeat this where ever you would like to place a bead on your I-Cord.
When you reach the stitch where you would like to have a bead, insert the right needle into it, but don't knit it just yet. Next, slide your bead up the yarn to the needle. Now, make the knit stitch, pulling the bead through the stitch along with the yarn. Continue knitting. On the next row when you get to the stitch with the bead on it, slide the bead up over the needle and to the back of the stitch. When you make the new stitch, the bead should pop out to the front of the I-Cord.
Here is a video demonstrating both of these methods.