most of the lists out there are very very incomplete. and alot of times people rant and rave about a few special plants and everyone starts to think those are the only cordage plants, but there are alot out there, some of my favorite arnt even from plants but the inner bark of trees such as the poplar tree. or willow. but of course, some are always better than others.
thistle, milkweed, dogbane, sedge, poplar inner bark, running ground pine, spruce roots, agave, basswood, nettles, yucca
but really thats just a few. something i learned from bow was when your walking through the woods or wherever, grab plants along the way and pull them, if it tugs you back, or you cant pull it up. you may have some good cordage material there.