8p near ramp
12g scout (except on 2 player maps)
25 range (-6 supply of zealots)
It's not my build, I stole it shamelessly from Bonyth and, as bw has been out for two decades, I'd assume he probably got it from somewhere. But it has been crushing stronger players than me at high A, it's ridiculously easy to execute and if the opponent doesn't react perfectly then they have a dozen ways they can throw the game instantly.
To execute it you send the first 3 zealots in a group to the other player's base and, if they've done a 1 gate opener, they will generally have at most 1 zealot and 1 dragoon.
If they offer to trade hits with you you can take the fight, dragoons do 50% vs zealot armour and zealots have higher dps anyway so 3 zealots > 1 zealot 1 dragoon. As you take the ramp try to position so all 3 can attack at once. If you fight them try to stutter your zealots further past his between attacks to make it harder for them to micro back.
If they're good they'll use the zealot to draw aggro but run it away. The goon will dance too obviously. Go to the mineral line and kill probes. The ones mining gas are the easiest ones to get so prioritize those if you can. Probe kills are preferred to killing the zealot if you have the option, the zealot doesn't help him much and may actually hurt him.
The goal of the zealots is twofold, scouting info and getting value. You'll get a much later scout than is usually possible in PvP, you should see the 3rd pylon (normally rules out proxy), goon range upgrade, and a 2nd goon finishing. That let's you rule out most tech cheeses. You may also see a 2nd gate.
You may also kill a zealot, force a shield battery, and kill probes. Your investment is about 250 mins (3 zealots lost but your scout probe lived) so if you kill 2 probes and force some drills it's basically fine.
You'll lose the zealots eventually but that's all part of the plan, you actually need to lose them to free up the supply you need to build dragoons which gets us to the next part of the build.
The moment your gas finishes you want 3 probes on it, you cannot afford delays here. Also make sure you cut the probe for the 21 gas, not 22 gas, you make it right after starting the 3rd zealot. As your zealots reach the opponent's ramp you should be able to start 2 dragoons. Shortly after that you should be able to get dragoon range and then, assuming you've successfully lost all 3 zealots, you can make another 2 dragoons. Making these on time is incredibly important because it opens up timing windows for the opponent to make mistakes. If your dragoons are late then the build stops working.
There are two key timing windows to be exploited here.
1. You can have 4 rangeless dragoons at your natural around the time that your opponent on 1 gate can have 1 zealot and 3 dragoons at your nat. This will happen most games, after cleaning up the 3 zealots most opponents will try to establish a soft contain with dragoons. If they do this you can simply micro your 4 dragoons onto their 3 and do stutter focus fire micro to inflict maximum damage as they try to retreat while not allowing the zealot to do any damage. Their first zealot still being alive can actually hurt them here, it is slower and will always die eventually if they cross the map but it can give them excess confidence which leads to dead goons and it can block the retreat of faster goons letting you do more damage. Your opponent will probably make this mistake and you can exploit it. Any dragoon trades you can take early on will compound your 2 gate advantage as you'd much rather have 5 vs 4 than 6 vs 5.
2. You can have 6 range dragoons at his natural around the time the opponent 5 range dragoons and a zealot on 1 gate. As before, this gives you a window to stutter in and focus down their dragoons while dodging the zealot. Additionally if they have placed a nex the nex will generally act to choke their dragoons, allow you to take a concave arc around the base of the ramp, and make any defence impossible.
After making 6 dragoons you can cut a dragoon for a zealot (you're tight on gas) and follow it up with a robo at the top of your ramp which, if you block the ramp, will be in time for dt and facilitate a transition into either a 2 gate + robo reaver bust or a no shuttle reaver expand.
It is very easy for the opponent to fall far behind from just the first 3 zealots. If the opponent made the safety zealot on 14 then they've already cut a probe compared to you to get their 16 pylon. If they take too much damage on their first zealot/dragoon they can easily lose one or both of them as their damage output is lower than your 3 zealots. If they panic and make a battery then they hurt themselves further as you don't have much interest in killing their fighting units, you're after probes, the battery is wasted money. It's not unusual to end up 6+ probes ahead from the zealots alone, you're up 1 from their supply block, your dragoons will generally get their scout probe while they're dealing with the zealots while your scout probe (if you sent one) got home alive because the zealots took over scouting, they will generally miss probe production while desperately trying not to die to your 3 zealots, they will often cut probes to rush out an extra gateway thinking you plan a committed zealot rush, and you can almost always kill a probe or two.
Once they've defended the zealots they will want to apply pressure, verify that you've not expanded, establish a loose contain, and generally get some value out of their faster goon range. As discussed above this encourages them to run head first with 3 dragoons into your 4 dragoon timing.
They may also want to continue to produce goons from 1 gate, add a robo around 28, then take a nexus when their mins hit 400. They can't hold that nexus due to the 6 range dragoons at their natural timing. Unless they added a quick second gate you will always have the 6 range dragoon timing and anything but being at the top of their ramp just loses them the game.
If they take minimal damage from the 3 zealots, don't fall into any of the traps, and build a reaver before leaving their base then they can be slightly ahead due to their earlier gas providing an edge in dragoon reaver fights. That's why I wouldn't advocate using this build vs Bisu if you ever happen to play him PvP. Also cross positions on some of the bigger maps makes the 6 range dragoon vs 5 at his nat timing a little shaky. But assuming that you're playing 2200 MMR and below this build just makes the matchup easy. The game starts and armed with the information above you just wait to see which of the pitfalls your opponent walks into. They lose the game for you, all you have to do is make 3 zealots, 2 dragoons, range, then 4 more dragoons.
It also freewins vs proxy 99 which makes it nice as a ladder build and it's pretty good vs 12 nex if you scout it early enough.
Replays and VODs available if anyone needs them. I'm not at my computer right now but comment if you want them and I'll deliver. You can also watch Bonyth's stream or get his rep packs, he uses it a lot, and far better than I do. I vaguely recall him using this over and over in the last BSL so I'd recommend those VODs as an example of this build working vs S rank Protoss.