Didn't see another thread like this, so I thought I would post some useful knots I use all the time in my practice poi and things I use them for. These are primarily knots I use with colecord poi, but I have used some of them to make handles on sock poi as well. Not so much for fire poi.
1.
Ashley's stopper knot: A big chunky knot that I use especially in my inner tube poi. I put one at the head of the poi because the inner wraps of this style of head are hard to get tight, and the coil can slide out a little when spun; the stopper makes sure this doesn't happen. I also use one to make a finger grip at the bottom of the cord (just above a loop I put around my pinkie and ring fingers). I also use it on my flowlights to use them as handles, on the end with two loops, by tucking single ends of cord through the top and tying Ashley's knots on the loose ends. Works as a nice chunky grip for socks.
2.
Lark's head: I use doubled cords for everything, which means I can use the
bight as an attachment point. In practice, I use either stable handle-cord combo and attach different heads at the bight, or I have a stable head/cord combo and use the bight to attach different handles. My newest pair has inner tube heads and two sets of handles: a loop with a spare bit of bight just above an Ashley's stopper, and a knob handle made of extra inner tube tied around a short bit of doubled colecord. The bight in the handles and in the main cord can be hitched together with a lark's head. Lark's head attachments when both ends of the line are loaded are both secure and easy to undo for quick change-outs. For situations where the lark's head would assume inconvenient shapes (when attaching it to a swivel, for instance, it can slip and wrap itself around the pivot) you can use the bight to form a lark's head around the standing end for a running knot that will not swallow up small rings. A good alternative to a palomar knot.
3. Double back knot: Tie an overhand knot, then take the working end, bring it back over the standing end and through the eye of the knot. Gives you a trifoil shaped knot that's chunky and doesn't kink the line. An alternative knot for most of the same things as the Ashley's. I use this more often for socks because it requires less slack to tie, though it's not as easy to undo as an Ashley's.
4.
Double overhand (running) knot: If you use the bight for your working end, keeping the standing end a single cord, you get a secure running knot that doesn't kink the line (much better than a single overhand running knot in both respects). [Edit: I forgot to mention what I use this for. This knot is what I use most often to attach the cord to my handles' swivels.]
Hopefully someone finds these useful. I have kind of a weird semi-autistic fascination with knots, so this post has been brewing in the back of my head for a while
