This is just part of the 5 S's technique.

https://www.healthline.com/health/baby/5-s-baby

Of them, I found swaddling, swaying/rocking, and shushing/singing the most effective for my kiddos.

100% of the time? No. But similar to this, holding them so they were lying face down on my arm instead of on their back worked a lot. I presume gas or some other reason that changing positions helped.

the 5 S's do work.. but also be aware that babies generally are crying for a reason. hungry? gassy? lonely? dirty?

check for their needs, give them attention, stimulate them.

Anything that makes a baby's brain go "wait, what is happening?" Will make them (momentarily) stop crying.

I mean, I don't know if it's specific to babies. For all I know that would calm me down if I'm pissed off or sad or angry too. Just got to find someone big enough to do it.

In my education, this was called The Charm Hold and is very useful for a gassy baby. Yet there are holds which are more useful for a gassy baby.

But you know what is most useful to make babies stop crying? Figure out what it is that they are communicating and act on it.

Sometimes you cannot figure it out because it is something like, "Dad, I need you to poke my left elbow five times while hopping on one foot," and so they have to cry until something else more pressing comes along that makes their elbow poking irrelevant.

Editing to Add: If you want to stop babies from crying and aren't going to do the figuring out bit, standing up and holding them vertically against you activates an old, old, old primate danger instinct where they will go silent so as not to attract the attention of the predator while the parent, whose fur their ancient instinct insists they are clinging to, makes the escape. Also, blowing in their face will get them to hold their breath momentarily, which has the side benefit of stopping crying. Cannot cry if you aren't breathing.

Editing a Second time to Add: Even my own child instantly stopped crying for the pediatrician when he (pediatrician) held my newborn away from me. It has less to do with how the pediatrician held the baby, and more to do with the fact that the pediatrician wasn't Momma or Dadda and my newborn's sensory awareness of the world couldn't locate Momma or Dadda. Danger! Ack! Better be silent to not attract predators while waiting for Momma or Dadda to come find me!

I liked putting them horizontal in my arms, and then moving them up and down vertically … like pure up/ down at a bit fast.

He’s also an expert baby appraiser:

https://m.youtube.com/watch?v=hPmCdoOgW_o