First class feature is Storm!
Storm has a huge number of benefits for pet builds as well as players seeking advantages in other ways. Storm has two sources of full damage conversion: 100% Cold to Vitality and 100% Lightning to Aether. Unlike most group damage conversions, these abilities affect pets as well. I would advise against running a pet build with Lightning to Aether conversion because the only group pet that specializes in Lightning [Occultist’s Raven] has a large Electrocute component that can’t be converted and Occultist is much better suited for Elemental than Aether anyway. The Cold to Vitality conversion, however, is a huge gold mine. Necromancer’s Reap Spirit and Bonescavenger Grips both contain pets that have dual Cold and Vitality damage, and converting all of the Cold damage to Vitality turns these pets into powerhouses. Storm also helps pets that primarily deal Physical damage: Storm provides at least 25% Physical to Cold or Lightning damage, assuming you at least soft cap its respective abilities. Cold conversion works wonders with the Winter King sword, and we all know the wrath of Lightning builds with Spark of Ultos and Glyph of Kelphat’Zoth rings. You can even take both skills and combine them with the Black Pendant rings (easily crafted at the Satyr in Devil’s Crossing) to get a full Elemental conversion build focusing on Cold and Lightning. With generous RR in not only Cold and Lightning, but Vitality and Aether as well and you have a wealth of possibilities to choose from.
The Storm Wisp is used largely as a defensive buff-bot. Its damage is Lightning, which helps Lightning pets even more, but its real utility is in its second ability which grants Elemental daamge and a large Elemental damage boost. Unfortunately, it makes the Wisp underwhelming if you’re going for Vitality or Aether, but considering there are already a good number of buffs / passives / RR to invest points into, leaving the Wisp out for these types of builds is not a big deal.
Even if you’re not playing a Summoner build, Storm has multiple passives which will greatly help you out. Storm provides a great Spirit boost for builds seeking an off-hand, and if your build’s main skill consumes a lot of Energy, its passive instantly replenishes part of your Energy once it reaches a threshhold. It’s the equivalent of using a potion without needing to use potions at all! The second ability is nearly just as good, as softcapping it gives you 10% DA as well as 30% Pierce resistance. The bottom skill provides an Energy shield that drastically raises your Elemental resistance on a short-term basis. It’s excellent if you’re going up against enemies that relish in their own RR abilities.
Storm is part of the GQ club, which means that players can roll for +1 to class bonus at the Satyr. If you’re not playing Beastcaller’s Lightning pets, this is a substantial boon as medals amount to a free class skills boost. For nearly all instances where I do a Satyr roll, I prefer the suffix “of the Wild;” Elemental Resistance and DA are highly coveted bonuses even for non-Summoner builds. Of course, with enough rolls, you’ll find a medal that gives you the class bonus and a suffix that sufficiently helps your character.
My builds focus on more interesting aspects, but if you’d like a standard pet build that can easily tear through content, standard pet builds in Vanilla can easily be outfitted to feature the Storm class.
Cold Pets: Nature + Storm: Winter King Sword for 50% conversion, Storm buff for 25% conversion, and 2 Black Pendant Rings to bring the total conversion to 82% Physical to Cold. Frostdread Curiass adds additional flat Cold damage to pets and make sure you craft a medal with Nature prefix to get additional pet %OA.
Lightning Pets: Shaman + Storm: Spark of Ultos for 25% conversion, Storm buff for 25% conversion, and 2 Glyph of Kelphat’Zoth rings to further increase pet Lightning damage. Voidmancer’s Cord is necessary as it provides a chance for huge Lightning damage. Shaman is more suited for this combination as the two rings give bonuses to Primal Spirit and you won’t have the luxury of bonus skill points like you would have with the Black Pendant rings. Nature can do this job as well - use Mantle of the Patron for Shoulder equipment if you’re not using Beastcaller’s.