I like all the deep-hook transitions and have been using the deep hook stuff for years. Ill say the swim move is my fav, as ive been landing it longer than any current arm-bar I still use. Surprisingly, the latest "deep-hook" for me to develop was the back widow.
Im loving Muddy Waters and that style of armbar. Muddy Waters is very popular at the moment, rightfully so, its a great path and the armbar from there is superb. Barncat has multiple ways he gets the muddy waters style of armbar, where the other arm is zombie and trapped. He's not only taking multiple paths to get it from RG, he's got entries from other positions as well. Ive been trying to practice a couple of these entries as I believe it is the most controlled and undefendable type of armbar. Right now though the swim move is still my ish.