Reviving items are quite possibly the most useful items for dungeoneers. Almost all of them allow you to bring others back from the dead, though, only within a very, very short timeframe of their death. There's also the Revives, allowing you to get back up and fighting as if nothing's happened after you get knocked out, and Miracle Seeds, which can bring new life to any garden.
The most ubiquitous of the reviving items are Reviver Seeds, letting you revive someone within a minute of their death. You'll have to be quick to get the seed to your fallen ally in time, but it'll be well worth it. Ingesting it is how it revives people, though if the fallen Pokemon does not have a mouth, crushing the sprout into a paste and putting that on the dead Pokemon works just as well.
Informally, Reviver Seeds are sometimes referred to as "Xerneas' Tears". Legend has it, that whenever a Pokemon dies, Xerneas sheds a tear, and those tears are Reviver Seeds. There's actually a lot of credence to this. Reviver Seeds are very commonly found around the Tree of Life, and they sprout into trees very similar to the Tree of Life, though on a much, much smaller scale.
When I asked Xerneas for their thoughts on the legend, they refused to comment, saying with a smile that "I want to keep the ambiguity of the legend alive."
As for the trees that sprout from Reviver Seeds, they're known as Saplings of Life, and while they bear the same rainbow leaves as the Tree of Life, they don't have a Xerneas to care for themselves. They're also rather tricky to maintain.
Saplings of life require a nearby stream of pure water, very fertile soil, and at least 20 hours of light a day. That might sound impossible, but sunlight isn't required, so a luminous orb can be used to keep it healthy.
This may sound like a lot, but it's well worth it, as it will supply you with a steady supply of Tiny Reviver Seeds. They aren't as potent as regular Reviver Seeds, and lack the heart-shaped bud at the end of their sprout, but they can still revive a Pokemon nonetheless, though the time it works for is stricter. They only reverse death if administered 20 seconds or less after death.
The seeds themselves actually don't do anything special when eaten, it's only the sprouts of Reviver and Tiny Reviver Seeds that revive Pokemon. What's left after the sprout is eaten is commonly called a "Plain Seed", though this name is actually a misnomer. Among those who grow plants, they're more often called "Miracle Seeds".
Miracle Seeds can sprout into any other plant. Oran bushes, pep-up plants, trees, one even reportedly sprouted into a Sunkern! Mulch made from them is also highly fertile, and very good for plants and grass-types. So don't throw your "Plain Seeds" away! Plant them, and see what you get!
Planting Miracle Seeds is a game of chance, since you have no idea what you're going to get. I personally recommend having a spot in your garden just for these seeds, then scatter a bunch of them and see what happens! Make sure to water them like almost any other plant, though, the chance that they'll need a fair amount of water is far greater than the chance that they'll need very little.
As for Tiny Reviver Seeds, they don't sprout into anything unique. They simply sprout into more Saplings of Life, if they can be kept alive.
Then there's Reviser Seeds. Don't let the similar name fool you, they're deadly to anyone who needs to breathe. They will revive you upon ingestion, but you'll then start uncontrollably laughing, until you suffocate to death. However, in a pinch, they can be used as makeshift reviver seeds, as long as you have a heal seed. The heal seed stops the laughter, and then the afflicted Pokemon can carry on with life as normal.
Nonetheless, Reviser Seeds are dangerous items, causing many deaths due to their near-identical appearance to Reviver Seeds
There's a way to distinguish between the two, however. The sprouts of Reviver Seeds always come out from the ridge of the seed, while with Reviser Seeds, the sprout is perpendicular to the ridge.
There's no Tiny Reviser Seeds, so Tiny Reviver Seeds are always safe. Just, be very careful with Reviver Seeds, and triple check to make sure they're not Reviser Seeds.
Reviser seeds have three separate legends behind them! One legend calls Reviser Seeds Xerneas' Mistake, and says that Xerneas accidentally creates them instead of Reviver Seeds sometimes.
Another legend, calling them Yveltal's Revenge, says that Reviser Seeds were instead created by Yveltal, after Reviver Seeds made deaths near nonexistent, and spread them across the world. It's said that the laughter the victims of these seeds have in their final moments isn't their own, but Yveltal's.
Yet another legend, calling them Zygarde's Compromise, has it that, long ago, Xerneas and Yveltal were fighting over the first Reviver Seeds. Yveltal wanted to destroy them and force Xerneas to never make another, while Xerneas wanted to keep them safe, and give them out to non-legendary Pokemon.
Zygarde, seeing this, came up with a compromise. Reviver seeds would exist, but in exchange, a near-identical seed that would cause a painful death upon ingestion would be created. Yveltal objected, insisting that she didn't want to cause any needless suffering. Zygarde obliged, and the three worked together to find a compromise: A seed that would kill any who ingest it, but in a completely painless manner, via ceaseless laughter.
Reviser Seed trees look like twisted old trees, with holes in their trunks that resemble the faces of various Pokemon laughing. They're haunting sights, especially if you see your own species' face in them. There's one near Mount Steel that looks like a Meganium laughing, and it always makes my petals tense up whenever I pass by it.
Revive All Orbs are the most legendary of all reviving items. They can revive anyone and everyone you know who has died within the past 10 minutes, all just by shattering the orb. However, there is no known way of creating them, they cannot be Recycled, and they are one of the rarest items to find in mystery dungeons. The most common way of finding them in mystery dungeons is, on rare occasions, Alpha Pokemon can be found with them.
However, rumors speak of another way. So-called "Illusory Grottos", low-danger mystery dungeons that only exist for hours before dissipating, are said to be filled with Revive All Orbs, as well as other reviving items. They're said to only open up in front of people who have recently suffered a great loss, such as a loved one dying, or a friendship ending. Vernir, Pahelia, and Ayueg all say they found one of these "Illusory Grottos" shortly after losing their partners, though they only found one Revive All Orb each. I personally believe the rumors to be true, though exaggerated.
Revive All Orbs are sometimes called "Xerneas' Blessing" or "Yeveltal's Condolences". Legend says that, long, long ago, a Ninetales' kit died, and the Ninetales traveled the world to find a legendary to reverse it.
One version of the legend says that the Ninetales came upon Xerneas, who bestowed upon her a massive orb to revive her kit, though it was already too late, as the kit's spirit had already moved on. In her grief, the Ninetales threw the orb into the sea, where it broke apart into Revive All Orbs, and those orbs scattered across the world.
The other version of the legend says that the Ninetales came upon Yveltal, who offered their condolences, as the kit's spirit had already moved on. The Ninetales pleaded with Yveltal to bring her kit's spirit back, but Yveltal said there was nothing she could do. However, Yveltal decided to work with Xerneas to create a charm that would prevent the Ninetales from ever losing another kit. Upon Yveltal giving the Ninetales the charm, though, she shouted hateful words towards Yveltal, and crushed the charm, before throwing its remains into the sea. Like with the other legend, those remains became Revive All Orbs, and scattered throughout the world.
Revives and Max Revives' names are misnomers, they don't actually do any reviving. Instead, if you're knocked out, they'll jolt you wide awake in an instant, letting you run away, or continue fighting. Max Revives will also heal you almost fully, though it won't help with paralysis, poison, sickness, or other ailments. Nonetheless, I'll cover how to make them here as well.
Revives are pretty simple to make. You'll need one Vivichoke, two Medicinal Leeks, a stirring implement, and for a Max Revive, two bunches of King's Leaves.
Mash the Vivichoke into a fine paste, then squeeze into the paste the juices from the Medicinal Leeks. Stir it with the implement until it begins to bubble, then let it sit. The mixture gets very hot during the process, so unless you're a fire type, you'll likely get burned if you don't use a stirring implement. Come back after an hour, and you should see yellow crystals beginning to form. Stir them so that they're bunched up together, let it sit for four more hours, and you'll have a fully formed Revive!
For a Max Revive, grind up the King's Leaves, and sprinkle them into the paste before adding the Medicinal Leek juices.
And that's all I have for reviving items! Essentials to have on your dungeon expeditions, in case the worst happens.
Next section, I'll be talking about warping items. Warp, Via, and Pure Seeds, Warp, Stayway, and Spurn orbs, Warp, Guiding, and Stayaway Wands, and the baffling existence of Warp Scarves.