There are many Gleipnir-like binders :
1. Their mid-line nipping nub may be a one-coil / single nipping loop, as in the original Gleipnir - or a multi-coil / double, or even triple nipping loop, which forms a longer "nipping tube", so it may be able to enclose ( and, presumably, grip more efficiently ) "twisted" around each other ends ( i.e., ends in an "elbow" configuration ( ABoK#35 ). Other, even more complex nipping structures ( preferably TIB ) may be used for the same purpose, as the Clove and the Cow/Girth hitch, the Constrictor, the Prusik, etc. However, it must be stressed that we do not know yet if those more complex nipping structures can really grip the pair of penetrating ends more efficiently than a single nipping loop, or not. Although they may appear to be more tightly closed around themselves, those convoluted structures may absorb, and then "waste" ( in the form of internal friction, within their over-entangled segments ) a substantial part of the total tensile forces - which, in a less convoluted structure, would had been transformed directly into constricting ( and thus locking ) power, applied where it is needed, around the penetrating ends, not within the nub itself !
2. Their two "circles" may en-circle the to-be-bound objects in one group, like a (two-line) double adjustable loop / tight noose, or in two groups, like a (one-line) handcuff.
3. The one part of the line, after it exits from the nipping structure, may encircle the object(s) following a clockwise course, and the other line following a counter-clockwise course, OR both lines can encircle the object following a course of the same handedness, both turning clockwise or both turning counter-clockwise.
However, I tend to believe that the most characteristic feature of a Gleipnir-like binder is that the ends of the encircling the object(s) lines enter into the nipping nub through opposite openings. This is paramount in achieving a "balance" of the nipping loop, and not allowing it to revolve around itself, and release its content, the penetrating ends. In a common tight hitch / binder, as the Bull-Clove hitch or the Double Ring hitch ( ABoK #1126 ), both ends enter into the nub through the same opening. Although they are tight double nooses / hitches which can also serve as binders, they do not look like Gleipnir-like binders to me...
Having said that, I have not yet made my mind about the binders of the second case of #3 ( as the binder #35, for example ). Are they Gleipnir-like binders, which look like double nooses, because of the same handedness of the courses followed by the two encircling lines ? OR they are double nooses, which look like Gleipnir-like binders, because the ends enter into the nipping nub through opposite openings ?