Hi! Me again!
Any suggestions for a general opener mood (or element) that I can use consistently to start a D&D session? Looking for a pavlovian “ok, we need to actually start playing or we’ll be here until 3am” type reaction as soon as I start to play it 
Will probably talk over it with a recap.
There’s a couple that are pretty good for that. There’s a piece of music called “A-team” in Tammeraut’s Fate II, which has some snare drums and an attention-getting military-like start to it. There’s the set Orientation I (from Kindled Magic) which has the “main title academy intro” which is a softer and more melodic tune, but very distinctive. In Goblin Arrows (from Lost Mine of Phandelver) the “A Wagon Ride of Phandalin” combines the one-shot “a hero’s entrance” with the element “hero music”, giving you both an attention-getting cheerful, driving tune that softens into encouraging but less attention-grabbing music for recap purposes. I also like several of the ones from the community content “Tabletop Music”, particularly “Asgard” (though the tunes there are shorter and you may want to turn them off before they repeat too many times, depending on the length of your recap).
Landed on The Path Yet Taken. But definitely found soundscapes for the others. Thanks!