I haven’t played or read enough PbtA to list a “favourite” move, but I like the Theorize move from Brindlewood Bay:

When the Mavens have an open, freewheeling discussion about the solution to a mystery based on the clues they have uncovered and reach a consensus, roll 2d6 plus the number of Clues found, minus the mystery’s complexity.
On a 10+, it’s the correct solution. The Keeper will provide an opportunity to take down the culprit or otherwise save the day.
On a 7-9, it’s the correct solution, but the Keeper will either add an unwelcome complication to the solution itself, or present a complicated or dangerous opportunity to take down the culprit and save the day.
On a 6-, the solution is incorrect, and the Keeper reacts.

I also like how that game’s Day and Night moves tweak the typical “Defy Danger” move.

My favorite PbtA is Ironsworn mainly how it handles progress tracks and how it encourages player agency in them. The best move is Fulfil Your Vow. Let me break it down and tell you about it.

When you achieve what you believe to be the fulfilment of your vow, roll the challenge dice and compare to your progress.

The trigger is not “when the tack is filled”, no-no-no. It is “what you believe to be the fulfilment of your vow” as in when the narrative is at such a place that the player thinks the vow is fulfilled. Say you are searching a tomb for a magical dagger. In a sarcophagus you find one. At this point the player can consider the vow fulfilled, or they can keep on working on the vow making sure they got the right one. They may have found it when the tack got filled, or when the first progress was marked. Up to the player to decide.

On a strong hit, your quest is complete.

You make a roll, compare the result to the progress marked on the track and on a strong hit the vow is fulfilled. Basic stuff.

On a weak hit, there is more to be done or you realize the truth of your quest.

The quest is done, the vow fulfilled. But there are complicating factors. Now we get into the juicy stuff. First you have to “Envision what you discover” as in what is the complicating factor. Perhaps the dagger is cursed? It is one of a pair? Guarded by a wraith who begins hunting whoever is wielding the dagger? This compication also mechanically drive the narrative forward as “You may Swear an Iron Vow to set things right”. Fix the new shit that got introduced by you trying to fulfil the vow with too little progress marked on the tracker. Juicy stuff.

On a miss, your quest is undone. Envision what happens, and choose one.

Traditional miss stuff, you don’t get what you want and bad things are happening. First option is “You recommit”, you try again but this time due to complications it will be harder. Perhaps the real dagger is in another tomb? Or that wraith guarding the tomb is wielding the dagger’s phantom representation and now you have to figure out how to materialize it. Second option is “You give up: Forsake Your Vow”. Forsake Your Vow is another move causing you distress as you abandon your promise and dedication. You suffer and others think less of you. In the eternal words of Nelson: har-har.