I am not aware of any more of Saintes Secret rooms, but there is a noteworthy correlation to the rooms. The fire from the first could relate to the lava pitt you use to enter, and the wind mentioned and used in this room could refer to the use of wind bursts to solve it. Potentially, this means the next room requires wind bursts to trigger?

Use a couple more ender pearls to navigate this weird tunnel and you will come to a sign,

This however is a FAKE end, and you will need to use your wind bursts and ender pearls again to find the real one.

I don't have an image of this room because I find it particularly hard to get past this sign,
You need to use your windburst behind you at the stone block in the tunnel. This triggers a double piston and lets you inside the room.

But it leads to another lectern with a hint.

The next step to entering requires a few wind bursts and a few ender pearls.

Face south west and use a wind burst into the corner. Then throw your enderpearl quickly into the tunnel that opens up.

(Facing Front)
(Facing Back -- behind you where you came from)

You now are in another tunnel thing to navigate.

The second secret room was found by the user AttackTeam

The entrance is this lava pool behind the nether building at spawn

Seems dangerous, right? Well the first step is to dive right in. Don't worry! It won't hurt ....

Dropping in flashes a sign with some coords. AttackTeam said it was a joke though.
[EDIT] I found said joke and it is just a sign from DystopiaBound

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Here is the view while you drop down, it may take a few minutes to get through all the cobwebs!

This provides us with our first hint to a secret place, alluded to be named the Cavern of Souls

This one is definitely harder of the secrets to describe, because it is the one I struggle with the most. I was snooping around when I came across one of these special areas in the nether. I consider this the easier (of the two I know of) to find due to it not needing any items.

Go to the nether and go on the weird walkway that is square shaped overviewing the whole thing.
On the left side, you will see a cave opening that blends in with the background. This is the entrance.

If you walk down, you will notice a very obvious lever. This controls a piston door.

This leads us to Saintes' (first?) Secret Room. It has a lectern with a hint alongside a decorative fire.

This isn't all, however. Outside the cave with the bamboo door you can find a stone alcove with a button hidden by a waterfall.

If you go inside, it looks a little intimidating.

But overall it is fine. You meet a totally trustworthy NPC at the end of the hallway.

To which find he sells totally legit merchandise, similar to the fellow below.

I don't have a clue where this connects to though, and just seems like a cute way to get Axolotl, Tropical Fish, and Pufferfish. If anyone finds connections to these villager npcs, let me know here!

While I am sure this may seem like a dead-end, there are OTHER villager NPCS with similar quest behavior.

If you go in the water plant tunnel thing under the mountain, you can find a bamboo trap door.

Entering such reveals another NPC, this one being seemingly unrelated to the other quest.

If you see what he has to trade, you can see he actually purchases diamonds to give you a new currency. Barnacle Coins!

While the quest is broken, I cannot actually obtain the items to give to the old man, but the reward would be a cactus called a camel treat.

I am not sure where the camel is or where this leads, hence why I wanted others to pitch in.
I know the quest can't be completed NOW but I like to document what was put on the server before.

When you go up the cherry tree, you find his daughter's house.

You can see her signs tell a similar story to the ones in the Old man's house, about missing the other and wanting to bring a souvenir. If you check her trades, you can find she wants to use Magic Meat, the reward for voting on the server.