This is all assuming that you placed a pylon at your nat, and if it was a 2+ player map, you built a Forge after scouting an empty main (and if it was a 4 player map, sending a second scouting probe after building the Forge)
5 Pool: Depending on how fast Protoss scouted the Zerg and how far the rush distance is, Protoss can choose to either complete their simcity or abandon the natural in favor for building a cannon in the main and 1-basing it.
In regards to the first option, Protoss will need to quickly plant 2 cannons, complete the simcity w/ a gateway and block with 5-6 probes (refer to Bisu vs 815 on FS in PL, Bisu vs Zero on Othello, Free vs Hyuk Andromeda). If you are able to complete your wall with another forge (or gate), you could get away with making only one cannon and warp in the second forge (cancelling it when the coast is clear), while getting away w/ less probes pulled (refer to Best vs Great on Dreamliner, just don't fuck up w/ the probe block.)
The other option is to warp a pylon in the main immediately and place a cannon in your mineral line, and go for either 2 gate pressure or 1 gate tech (refer to Bisu vs keke on Neo Medusa). I don't really know much about this option so someone more knowledgeable about this should enlighten us on this ^^
9 Pool Gas: Generally, speedlings will be on the way. 2 Cannons after your forge, cut probes at 15. A Nexus and Gateway at 15, and resume probe production after the Gateway. 16 pylon, gas afterwards, etc etc. Pull a couple of probes to block speedlings from darting in. Try to keep your scouting probe alive to see if he's getting speed on his lings (generally yes, but he could also be going for a retardedly fast lair). Depending on how big the hole is in your simcity, it's your choice to build another pylon or a core to fill the hole.
9 Pool: One cannon must go up for sure. If he makes 6 lings, then you will have to make 2 cannons to have sufficient defense. Nexus-Gate afterwards ofc
Overpool: I'm not exactly sure how to verify this in-game, but the proper response is Forge-Nexus, followed by a probe cut and an immediate cannon.
12 Pool: Forge-Nexus-Cannon, I'm assuming. It might be possible to get away with a Nexus first, but I'm not very sure about the timings against this build, so someone more familiar with the timings against this build speak up ^^
Liquipedia says 14 Nex/14 Forge >__>
12 Hatch: If you scouted him first, you get to have the pleasure of going Nexus-Forge-Gate (or Gate-Forge, not sure if you can do this on a normal map), If you scouted him second, going Forge-Nexus-Gate-Cannon is sufficient. If you did go Nexus first, you should skip the second pylon.
3 Hatch No Pool: I'm unfamiliar with the proper counter to this build. Doing a cannon rush is possible, and I've gotten away with going Nexus-Gate-Core-Forge against this build. Somebody more knowledgeable please enlighten us ^^
So Liquipedia says to 2 Gate after making the Nexus, but I don't ever recall seeing that in progames. Any VODs/reps on this?
I do realize that there are map attributes that allows for Protoss to be exceptionally greedy, namely maps that have an huge rush distance and/or have naturals that can be completely walled-in, or the main/nat sharing 1 small ramp (Benzene, Longinus, Triathlon to name a few), The exact details about how much Protoss can get away with, I'm not sure at all, so those with more game knowledge please input your thoughts on these map-specific things where Protoss can get away with more :D
Also regarding nat gas timings, which many people don't actually know for sure, I'm certain you build it when your Core is halfway finished, or at least before its finished preferably.
also if there are any corrections to be made (surely there is at least one lol), or things to be added, please do say so.
edit: oh.. a lot of this was already covered in Liquipedia >< I don't remember seeing that section there before, but I should've checked before I hit post D: At the very least I put in stuff about vs 5pool and map attributes that allow for greedier play >__>