Buddhist wear red strings on their wrists or necks, etc. as a blessing; the strings are blessed by lamas and therefore have an energetic bond. There seems to be no particular emphasis on where or how to use them, although some Buddhists have great faith in their power.

I have heard of some other (Western) groups that wear strings, but I do not know anything else about it.

In the Gnostic tradition, there are various amulets or talismans that you can make for yourself, but none are a mere string.