(Apologies if this is not of an appropriate form. I can certainly split to separate messages. I haven’t been around these parts since ~2006. 
I propose the Double Ganging Loop, Double Blood Ganging Loop, the (single) Ganging Loop, and the Blood Ganging Loop. All can be formed in the bight. While the single Ganging Loop is equivalent to ABOK 276 (the “ganging knot”, hence the name here), and I’ll present one method of tying previously discussed in this forum, I will also present one simpler approaching to tying it in the bight and another approach that is more naturally related to the double loop and blood knot variants. Understanding these methods of tying #276 aide in forming the other loops.
Given that this double loop is so simple it surely must exist already, but I’ve not found it in ABOK (see Comparisons below). It may be hiding in a lanyard/button section. Nevertheless, I’m happy to present these alternate tying methods which seem simpler than #276.
Single Ganging Loop, slip loop method:
Equivalent to the method suggested in https://igkt.net/sm/index.php?topic=4232.0 a slip knot loop is created. My 5/14 drawing shows forming a bight in the loop and passing the upper section through the overhand, then fully tightening the overhand. Either the loop or running end can be pulled to collapse the upper loop into a half hitch.
https://i.imgur.com/1aU0tn1.jpg
Single Ganging Loop, single loop method:
More naturally as a single loop for a hanging line, take a bight on the left, add two clockwise twists, pass it behind the standing part and down through the hole. Hold the standing end and running part in one hand, and the part of the loop connected to the overhand knot in the other, and tighten the overhand. Either the loop or running end can be pulled to collapse the upper loop into a half hitch.
https://i.imgur.com/GpOv2RI.jpg
Single Ganging Loop, butterfly method:
Take a bight with single clockwise twist (similar to a butterfly loop knot), pass the bight/loop forward over the twist then behind. In the diagram two loops are formed and passed through to create the overhands. If only one such loop and overhand is created and tightened, the remaining loop can be collapsed into the half hitch as above.
https://i.imgur.com/gjFSRoJ.jpg
Double Ganging Loop
The double loop can be formed directly from #276 before collapsing the upper loop into the half hitch. The overhand being first tightened in either of the first two methods, form the upper overhand as shown. Note that this is easy to get “backwards”; the overhand can be tightened by pulling on the upper loop and running end; if it immediately collapses the overhand knot, tie it by forming the loop with the other half. As seen in the middle diagram, the two final loops are connected.
https://i.imgur.com/CfLywTX.jpg
https://i.imgur.com/EGazBPY.jpg
Here is the Double Ganging Loop tied starting from the single loop variant.
https://i.imgur.com/tblXoQ3.jpg
https://i.imgur.com/LWCD5Z7.jpg
https://i.imgur.com/AkOwEjl.jpg
https://i.imgur.com/kj4Batz.jpg
https://i.imgur.com/fcQQ2kC.jpg
(If the running end is tightened, this forms ABOK #276, instead…)
https://i.imgur.com/Vn3Z0gb.jpg
https://i.imgur.com/G1GVR2n.jpg
https://i.imgur.com/xkBahzb.jpg
Tighten by pulling the standing and running end.
https://i.imgur.com/IABkGUz.jpg
At this point the center section shows a third loop, which could be extracted to form a Triple Ganging Loop, but otherwise pull the loops to remoev it back into the center section.
https://i.imgur.com/hvnVXE7.jpg
Here is the final double loop, back side, and showing that the loops are connected like the Spanish bowline.
https://i.imgur.com/LRmNiM0.jpg
https://i.imgur.com/ZZ6gXR2.jpg
https://i.imgur.com/z97q4Mg.jpg
Double Blood Ganging Loop
The butterfly tying method and single loop method can take an additional turn around before passing through each loop that forms the overhand, forming blood knots.
https://i.imgur.com/u3W1SDD.jpg
https://i.imgur.com/E4itIsN.jpg
https://i.imgur.com/alIz7tC.jpg
https://i.imgur.com/MyDDA11.jpg
As the loops can be arranged on the same side of the standing-running ends, this makes a reasonable double loop for 45-degree pull downward (staking to the ground) or upward (supporting a clothesline).
b Blood Ganging Loop[/b]
By omitting the second loop a ganging knot is created that uses a blood knot / double overhand and two half hitches. Here it is shown by removing the second loop from the double.
https://i.imgur.com/KIvraFG.jpg
https://i.imgur.com/9SrYHwS.jpg
https://i.imgur.com/0N4EmMO.jpg
https://i.imgur.com/qy7sAxg.jpg
https://i.imgur.com/rCTtoKW.jpg
https://i.imgur.com/iJnjDRV.jpg
History
On Friday, May 14, while analyzing some luff-upon-luff, two-fold purchase, and trucker’s hitches, I was considering the butterfly knot and looked at some variations that ultimately led to the double loop version. Collapsing the double loop into its various forms revealed the alternate methods of tying. Similarities were reviewed in ABOK but the 2013 forum post pointed me toward #276 which I was able to eventually verify as equivalent (I was working with a mirrored form in my diagrams, and the method in Ashley is… nontrivial).
The methods of tying above seem much easier than #276, where it’s not clear how the half hitch is formed, since it doesn’t look like you’d be passing the hitch over the loop. It’s also necessary to collapse that half hitch to form the appropriate bend of the thumb/finger end of the line, which is also not very clear from those diagrams.
Structure
I had initially coined this the “hitched slip knot” in the single loop form, in contrast to a “slip knot and half hitch” (ABOK 1021). The double loop variant therefore seemed like a “double hitched slip knot”, then a “hitched blood knot” / “double hitched blood knot”. Compared with the English Knot (ABOK 496) it seems like an “English knot in the bight”.
Comparisons
The single loop (ABOK 276) was compared against 286, 1016, 1043, 1045. No obvious method to start with 1045 was found.
Double loops 1088, 1090–96 were considered, with none of 1090–96 matching. The Sheepshank (1088) would require the half hitches to be formed in the other directions and the ends passed through the middle of the hitches on the opposite side. The double ganging loop is therefore something like an “overhand reverse sheepshank” as it purposefully collapses on loading.
The Commercial Curtain Cord Holdback (ABOK 1113) is asymmetric as one end collapses the knot, but does provide the strangle knot around one of the loops. In the form of 1113, however, it doesn’t collapse back to 276, so trying the free loop around the right-hand end will not yield the same double loop knot.
The various bights 1140–1170 are obviously similar but the forces are outward (Sheepshanks).