Top 2 Best Popular Ball Lightning Builds in PoE 3.5

1. PoE 3.5 HCSSF! Poison Balls of Knockback Builds

Aiming to hit as significantly as possible with Ball lightning to stack poison adding the opportunity to knock back and blind seemed to synergize so properly any enemy not immune to knockback won't be capable of touch you and having just about every enemies opportunity to hit!?

Pros & Cons:
+ Cheap to build, Actually free to build SSF don't need any uniques and only need 4 links.
+ Multi-Level defenses (Meatshields>Reduced Movespeed/ActionSpeed>"Evasion">Block>max Endurance charges/Immortal call>Energy Shield>Mind of matter>Armour/Life)
+ Makes non-knockback immune enemies trivial
+ FUN! To not just kill but push enemies into a corner (Especially bosses) as your cronies beat them up >:)
+ Versatile leveling (And somewhat versatile end game build)
+ Summoner build that doesn't need to manually cast any summoning spells. (Casting Ball lightning will automatically summon Sentinels/Scorpion)

- None that I can think of, Well none that doesn't apply to every single build.
- Uniques can improve the build, More expensive ones improve it better.
- 6linked items improve the build.
- Doing it SSF can use a lot of Chromas, Jewelers, Fusings to get the right gems in the right spots.
- There are tankier builds and builds that do more DPS
- Guess there might be one, Build path is a bit stretched out

Skill Gems:
Example build with only 4links:
4L Ball Lightning-KnockBack-Blind-Posion
4L HeraldOfAgony-HeraldOfPurity-MinionDMG-FasterAttacks
4L ArmageddonBrand-CurseOnHit-Enfeeble-TemporalChains
4L CastWhenDamageTaken-ImmortalCall-IncreasedDuration-Enfeeble
3L SpellTotem-VaalSummonSkeleton-Maim
2L FlameDash-FasterCasting

Core:
- Ball lightning - Poison - Added Knockback - Blind (Essentially 100% possibility to continuously do 100% increased Knockback and lessen the opportunity to hit by 50% and lowers the light radius to the minimum value and reduce the effective critical strike opportunity)
- Herald of Agony (Gives poison possibility and Summons Scorpion as the main goal behind the build)
- Herald of Purity (Adds physical damage to spells so they can poison to summon Herald of Agony, Summons Genitals to distract/kill enemies, with 10% likelihood to summon on rare/unique hit have 100% uptime, without needing to resummon if compared to using zombies for the same purpose)
- Brand - Curse on hit - Enfeeble - Temporal Chains, Spread curses to enemies and keep them on bosses for longer.
- Cast When Damage Taken - Immortal Call

Gems Link:
Supports probable for
"Ball lightning - Added Knockback support - Blind" (Goal isn't damage but on hit applications)
- Knockback, Crowd controls a lot of enemies, But also just happens to increase our DPS but the unspecified amount by keeping enemies in range. (Imagine ball lightning going towards an enemy while they run at you, Hits them once then goes past, But with knockback when the ball hits the enemy it will push them back with the ball getting the full duration of DMG!)
- Blind, It's a great ailment but only 10% possibility to apply. Good thing we are aiming to hit over 10 times a second at 10% each hit! ;)
- Lesser poison(40%) support, Ideally Poison(60%) support as you just want the possibility to poison the physical damage isn't needed to poison, Herald of Purity covers that.
- Faster casting, Faster/more spells cast more on hit applications.
- Spell echo, ^
- Slower projectiles, More hits on immobile bosses (the bunch of other minor benefits as more hits on enemies against the wall before the projectile hits the wall and disappears etc, But it is slower clear speed)
- Lesser multiple projectiles, Volley, Greater Multiple projectiles, They are fun to see all the balls hitting a greater area! But I am uncertain if multiple balls from the same cast can "Hit" the same target (From what I could find out they cannot "Damage" the same target but do they "Hit" and do 0 damage? I dunno) One ball is good enough imo if you pull and aim properly though.

For
"Herald of Agony"
- Peirce
- Minion damage
- Damage to full life
- Vile toxins
- Faster Attacks
- Lesser/Greater Multiple projectiles

For
"Herald of Purity"
Basically the same as Herald of Agony without Pierce, Lesser/Greater Multiple Projectiles and Damage on a full life. (AS they don't use projectiles and can take damage, Unlike Herald of Agony)
Also, a plus to using Herald of Purity just hypothetically if you treated them as equals to zombies, Having HoP consistently spawn at max spawns without needing to press any summon button or manually cast as they spawn automatically, Is so much more convenient and smooth gameplay then doing a zombie build.

With heralds the biggest issue is mana reservation, Needing to balance how strong you want them to be with how much manage you want to be left over to make Mind over matter more effective. (And also casting skills).

For
"Brand - Curse on the hit"
Basically wanted skill to apply curses and decided on brands, I used Enfeeble (Reduced Accuracy, Critical Strike Opportunity, Damage, Critical Strike Multiplier) and Temporal Chains (Less Action Speed, Other effects on Cursed enemies expire 40% slower) for defense If you feel like using different curses feel free.
Projectile weakness can add even more knockback!
I used Armageddon brand, To be honest just because I think it looks cooler then Storm brand. But I think Storm brand might be better, Hits seem possibly guaranteed, But Armageddon Brand would hit more enemies once you push them all together with knockback so I think both would work.
Reason for brands, You get 5 seconds brand application + curse length after.
Considered Orb of storms which last 6 seconds but mobile enemies/bosses can be annoying to keep recasting it just about every time they move brands stick to the enemies with the added bonuses of attaching to new mobs if first one dies. (And brands have 0.10sec faster cast time which is more important then you might think when casting them a lot makes it feel way more smooth to just quickly throw out 1-3 before Ball Lightning)
When clearing trash mobs actually feels smooth to cast a brand then Ball lightning because you knock back the enemies into each other so the brand has plenty of targets to reattach to (Like putting a bomb one enemy throwing them into a crowd), Whereas Orb of Storms enemies would be pushed out of range very quickly.

For
Cast When Damage Taken - Immortal Call
I used increased duration and Enfeeble, Yes I already have the brands applying higher levels of Enfeeble but I just like the piece of mind if something big hits me if I missed it with brands or its off screen then it will at least get some dmg and accuracy reduction.
- Discharge, Since you have a max of all the charges easily
- Life leech, if used with something damaging like Discharge
- Vortex, Cold Snap, Arctic Breath, Ice Nova, Chill enemies
- Convocation to bring minions to you
- Golem (so you don't need to manually recast)
- Ball Lightning/Orb of Storms/Firestorm to have more on the hit

Summon Phantasm on Kill support:
Mixed feelings on this support.
Adds distraction minions, Can add to anything in this build really and goes effectively with Herald of agony supports (Greater Multiple projectiles, Piercing, Minion damage, So you can get support gems effecting both, But they attack with spells so not Faster Attacks)

Video:

PoB Link: https://pastebin.com/rxprpyWS
Skill Tree: https://tinyurl.com/ybzlh6qu
Example Link: http://www.pathofexile.com/forum/view-thread/2288257


2. PoE 3.5 Katmos's Bosskiller Necromantic Agoniser Guide Builds

This is a guide that requires only minimal knowledge about minions and will explain the build’s choices as they follow. Also, if you like video guides, this one has one attached (see below). This guide will be updated periodically.
Also, I chose to not put too many spoilers, but instead write plain text, because a lot of people use mobile phones to read guides, and those devices may have problems with opening spoilers.
This build was designed in Delve league (patch 3.4), however, there were no significant changes for patch 3.5. and remains pretty much the same.

Maps up to tier 15, bosses included, but not guardians or Shaper, because those hit hard behind your meat-shield. PoB calculates fully buffed Agony Crawler damage at 1.135.001 Dps including poison against regular bosses (more than 1 million Dps for under 1 exalted orb!!!). The important part is the safety in disrupting the boss with various minions into not attacking the character, though. You can safely run unidentified rare red maps, but you must play carefully.
In case of elemental reflect, you will have to swap your high-level Ball Lightning with a level 1 gem. Also, with a shaper’s ring having mana gained on hit with spells mod, you can run maps with no mana regeneration.

Pros & Cons:
+ Safe
+ Can run all map mods (see below) and all tiers up to T15 for sure. I don't have the agility to run guardians and Elder/Shaper, but the damage and defenses are certainly viable (so good, non-lazy players should run these, too) as PoB calculates damage at over 1 million dps.
+ Has up to 5 gem slots to customize, 6 if you get a stygian vise belt
+ Only 1 mandatory unique item required: Volkuur's guidance zealot gloves (but it doesn’t cost more than 1 alchemy/chaos orb, so it's very cheap)
+ Overcapped elemental resistances, and more than 20% chaos resistance, all from rare items and jewels
+ More than 7000 life (considering that most builds have ~ 5ooo life without expensive items like Belly of the Beast or Kaom’s Heart), and apart from that, with all those meat-shield minions, you are quite tanky.
+ Very cheap to start (if you just want to reliably run yellow maps, only 5-links are enough, and the total cost without jewels is ~10 chaos orbs). It is also one of the cheapest builds to safely run red maps, but you’ll need some investment on that, ~ 1-2 exalts.
+ Lots of meat-shield minions (10 zombies, 1 chaos golem, 2 specters, 1 Animated Guardian) to protect you (3 specters if you use boots with a +1 specter delve mod on them)
+ Decoy totem to distract the boss
+ Destroys corpses, so that you don’t have to worry about reanimators
+ Non-meta (only 2-3% of players play it), so there is a low chance of it getting nerfed. It cleans maps fast enough, though, because the agony crawler has a split-arrow ranged attack built into it.
+ Minions are resistance-capped too
+ Safe from porcupine explosions, because your meat-shield minions stand in their way.
+ Great physical damage reduction: 10% from zombies, 4% from chaos golem, 15% from basalt flask = a grand total of 29 % physical damage reduction
+ Animated guardian has just under 40.000 life, more than 1600 life regen/sec, with only 7-8 chaos orbs worth of gear, and it increases the damage of other minions, and curses enemies with level 10 temporal chains on hit!
+ Great league starter!

- The agony crawler +Clarity (level 1) reserve 87% of your mana, so you won’t be able to cast any other auras, but generally, you should not have problems with it
- Summoners are not for everyone, but it has a lot of direct casting and flask button-pushing to compensate so you won’t get bored.
- Summoners are generally not for PvP.
- Channeler builds, meaning you have to stay in one place to keep buffing the agony crawler, and because of that, bosses that can hit behind your meat-wall are very risky. Most Guardians, the Shaper/Elder, and all Kitava variants are extremely dangerous. All other bosses are very easy to kill.

Ascendancy:
Go necromancer, as it allows you to toughen up your meat shield minions a lot. Order of importance:
1. Invoker
2. Commander of darkness
3. Flesh binder
4. Puppetmaster for mob-killing / Soul weaver if you want the build to be more of a boss-killer

Bandits:
Kill all for 2 extra passive skill points.

Pantheon:
Major god: the soul of Solaris for general boss mapping, the soul of Lunaris for delving
Minor god: the soul of Tukohama or Ryslatha
Of course, you can always change them in town/hideout to better fit the map you want to run.

Playstyle:
Channel –cast Wither on the enemy in order to simultaneously:
- get your minions over there to move/attack (minion AI is very dumb in this game, but only for your minions, not for bosses like Izaro or guardians)
- lower the enemy chaos resistance in the area
- auto-cast Ball lightning spells, in order to summon and empower the Agony Crawler
- decrease enemy movement speed.
While in the Azurite mine, opening strongboxes or simply in tight situations, simply use your quartz flask to phase out of the pinch.
From time to time, cast spirit offering to add chaos damage to your minions and increase their resistance.
This build has the general playstyle of a specter summoner build, but it's more suited for a full life build, instead of a low life midnight bargain specter variant.

Video:
Tier 7 Zana mission

Apex of Sacrifice run

Tier 12 map

short T11 boss fight

PoB Link: https://pastebin.com/RJxVmThE
Skill Tree: https://tinyurl.com/y86kkl3j

Example Link: http://www.pathofexile.com/forum/view-thread/2220147