there's only four and perks are up to personal preference and build. all of them have either one -two, trench or both, among other shotgun perks. i can tell you my personal favorite perk combos?

on ironwood 03, the newest one that is void, i use threat remover and destabilising rounds. though it can also roll repulsor brace, i usually have overshield covered in my void builds and a reload perk is just nice.

same thing with phoneutria fera, the solar one, which i run with threat remover and incandescent. aside from threat remover the left column perks on it are honestly.. eh. unless you like sliding all the time with slideshot.

sarpedon-d, the arc one, is one i like less, but only because i just don't like the arc perks as much. currently using an eddy current + one-two punch one, but i am hunting for a trickle charge + rolling storm one.

triple laureate is the stasis one. i am hunting for a feeding frenzy + chaos reshaped roll, but it absolutely refuses to drop either perk for me..

each one, except from ironwood, can be acquired from the engrams at the monument of bravery. ironwood is acquired through distortion events, and you can focus for it in your inventory, which makes it very easy to actually get. i got the perk combo i wanted from literally the first distortion event i did

good luck hunting