tl;dr CI HoT Autobomber with Herald of Ice pops and Crest of Desire. My first mostly-self-made build, though it borrows better players' concepts (such as CWDT Crackling Lance). Note: the build is very vulnerable to oneshots and so not good for XP gain.

About My Herald of Thunder Autobomber

My build functions by using a decent Crest of Desire helm to add 100% more damage, +8 gem levels and ~40% hit frequency to Herald of Thunder, saving mana reservation to do a 4L Herald of Ice for clear and a Discipline aura. I use (i) two large clusters and a cold damage Light of Meaning, (ii) the "freeze duration" cold mastery and Brine Bound Ascendancy notable (1s min freeze duration), and (iii) 6L CWDT Crackling Lance to provide big shocks (usually 50-60%) to prop up single target DPS.

I enjoy how weird Crest of Desire (shoutout to Mathil's Tornado build from a while back) is, so I wanted to make this build work with that item while the autobomber mechanics are so accessible in this event. Objectively better builds have been posted here, but I wanted to share mine in case any other Celestial Herald Effect MTX enjoyers want out from under the thumb of Big Inpulsa.

Budget: probably 15-20 divine. I upgraded incrementally so it didn't feel expensive. Big-ticket item is a Crystal Belt with 154 ES, 109% resists, and crafted 17% damage - have you checked in on Rog lately?

Pros

• MTX-enhanced Herald of Ice pops
• 10 Hz hit rate!
• Cheap to get started - I started with +7/40% helm and 2x rings
• Keep body, glove slots for rare gear
• Guaranteed crits
• Helmet provides most of the damage
• Get to use aura(s) due to no Lone Messenger
• Surprisingly okay single target DPS

Cons

• Can't see shit due to MTX-enhanced Herald of Ice pops
• 10 Hz self-hit rate...
• Defense layers: freeze, ~4.5k ES, portals - very vulnerable to oneshots
• Lose ~~Heatshiver~~helm slot
• Lower HoT damage ceiling than other similar builds
• Terrible handful-of-targets DPS
• Getting enough ES for leech to feel good won't be cheap

Learnings from my first build, other thoughts

• "The damage inflicted by this skill is not affected by modifiers to spell damage" is a lot more all-encompassing than I thought. Finding ways to boost HoT DPS was a fun puzzle.
• Getting enough ES so 10% instant leech offsets 10 Hz self-hits was not easy. My body armour and belt carry my ES hard, allowing me to put a couple points into damage and AoE.
• I started with hybrid life/ES, Petrified Blood, and Corrupted Soul, but had a difficult time solving chaos damage while keeping fire/cold/light resistance capped. I decided to bypass this by just going CI; my ~1.5k chaos max hit rose to 5k phys max hit. This is a buff.
• I tried an ES gain on hit Watcher's Eye and it didn't feel like it was doing much.
• I was too lazy to try CWDT Immortal Call (too much strength required) or to get more reservation efficiency to use Flesh and Stone. Also I did not quality many of my gems or get awakened supports as they would not improve HoT's DPS.
• I feel like there is probably a good Thread of Hope or Impossible Escape I could use to eke out more damage, but I am probably moving on before I figure it out.
• Crest of Desire gives a lot of extra hit rate, which would theoretically open up a ring slot for e.g. Polaric Devastation, Circle of Ambition, etc.
• I could have bought XP carries to get a few more points (either into the Light of Meaning or over to my anointed notable so I could anoint another), but am too lazy. Similarly, I was too lazy to buy a good Vaal Discipline gem.
• Overall I had a ton of fun tinkering with this without a guide and am surprised it even got to T16.

Current PoB link

(assumes. 5s freeze boost, 50% shock, 30% chill)

Videos (unflattering but more realistic one first)

T16 Beach [feat. oneshot]

T16 Ashen Wood

T16 Lighthouse

Very boring Chayula Breachstone [feat. 64% shock on the boss]

edit: why am I chugging a life flask? This was my solution to Corrupted Blood and bleed that was leftover from my leveling build... have we established that I'm lazy yet?

edit2: updated pobb.in to reflect a flask change not captured by the original.

edit3: updated pobb.in to ditch two nonfunctional masteries leftover from the life/ES build; net gain of ~2.5% DPS and some AoE.

edit4: ditched reservation cluster (it was providing mostly aura effect, which is not huge for this build) and two AoE nodes to path to Frost Walker. Net gain ~5% dps over the version in the video, net loss of some mana and ~100 ES.