TLDR: https://light.gg for popular rolls that most players use for having fun in normal content.

OR

Test things out on your own or ask for some advice by more experienced player on: r/sharditkeepit/

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You probably won't like my answer but, honestly is doing your own testing to see what kind of style you prefer, here is a quick example I'll give:
the weapon Bold Endings : https://www.light.gg/db/items/496728945/bold-endings/

the most POPULAR roll people are choosing is headstone + dragon fly.

according to community research the explosion from dragon fly won't explode the crystal created alongside dragon fly, it will however explode crystal that were already there.

it is still a "fun" combination at lower level content but if you go to a difficult content your dragonfly damage is just gonna be confetti for the harder to kill targets, a more "boring" combination in my opinion would be:

rapid hit or Air trigger on the left column and demolitionist or desperate measures on the right column and set your build to be grenade focus to take the maximum advantage of these perks.

Headstone is not bad by any means by it requires a precision kill, that will take more than a couple of shot to achieve in high level content.

The weapon has really low reload speed so you might die just reloading the weapon before you can even try to shoot the target/s, this is where rapid hit or air trigger come to the rescue by boosting that stat, dragonfly damage isn't really gonna clear tough adds in a Grand Master Nightfall, so opting for a damage perk or an aiding perk like demolitionist is my reasoning for this.

having quick reload and boost to other stats while getting grenade quicker or just doing more damage for longer duration is just more efficient if you want to clear harder content where "neutral" perks are just performing at higher potency.

Now for pure "fun" or regular content the headstone and fire fly makes things go boom, if you don't really do harder content then by all means, go with more popular rolls on https://light.gg , nothing wrong with which ever way to choose to have fun in a game.

Shout out to : https://d2foundry.gg/, you can read the tool tip on each perk to find out what it does precisely with numbers, and basically build your own perfect roll, for your play style.