New Year Resolutions don't need to wait. The sooner I start, the sooner I could be done with one. The context for these is here.
1d10 Skylands of Vestigia, vol. 1
Massive primordial clock Metronomicon ticks ever since this skyland came to be when the Shadowfell collided with Dis, the second circle of Nine Hells. Metals found in the pits of Dis have been possessed by the tormented souls of Shadowfell, ringing their weeps of agony. The only thing that it missed was a spark of inspiration, which occurred when the Elemental Plane of Lightning passed by. All it took was a single spark to bring life to this skyland. Fiends, undead, and the mortals stuck in between fight for the rulership over this skyland by combining the martial prowess with the dissonant music natural to their home.
Another skyland that's in constant conflict happens to be a collision of the Ysgard with Feywild. The result is a land of uneven battle, between the fairies and the nonmagical giants. While one of the sides is obviously much more powerful when it comes to pure physical strength, the other side possesses greater magic potential. The result is a fairly balanced fight of the greatest proportions, puns very intended.
3. The Wild Crest
A black salt desert of an unknown origin has attracted adventurers ever since people discovered blackrocks deep beneath the salts. Rumors have it that this used to be some unspecified layer of Abyss that was an ocean dried out by the collision with the Elemental Plane of Fire. Once the blackrock is crushed into a fine powder, it becomes flammable. People who live here are rather religious, vary of monsters like fiends or undead, and most live off of either their crops if possible, or by herding the cattle.
4. Baldur's Fate
Myths say that this city used to be in the Material Plane itself, found in a location called Word Coast. Even before the beginning of Vestigia, this city was a port. Back then, it was however a port for sea ships. The structure and infrastructure were there, but the city has been partially rebuilt in order to serve as a proper port for skyships.
People doubted the existence of something as ridiculous as the Elemental Plane of Snakes, the true origin of creatures such as yuan-ti or naga. They have been proven wrong once this plane collided with just a small fraction of the Limbo, as well as a shard of Mechanus stuck in one mad inventor's head. Ever since the snake elementals have been much more... mouldable by those who populate this land, and much more submissive to the commands given to them. They could be stretched to incredible lengths, rolled to be extremely thin, or even contracted. Those who populate this island soon discovered how to change their colors on command, react to things these snakes can see, hear, feel, or even smell, and even how to produce words and other sounds. It's hard to even tell if these snakes are alive anymore, or if they are just objects that resemble snakes. Through years of trial and error, the snake-based technology arose, so incredibly complex that a human couldn't understand it within one lifetime. The most complicated of their creations, however, has to be the Labyrinth, a network of snaketech machinery that connects the vast majority of the devices on this island and allows for nearly instantaneous communication between the snake-based creations.
All of this came to be underneath the rulership of the Serpent Empress, the one true ruler of the former Elemental Plane of Snakes. Her ultimate plan is to take over this wretched world and connect it whole with her network of snakes. However, things may change, for the rebels are among the common folk, scheming their plans of overthrowing the true empress. Rumors have it that some elves are assisting them.
The collision of a small chunk of Acheron with a portion of Beastlands had catastrophic consequences for the formerly good-aligned plane. The wilderness has been forced to change in order to survive, adapting to the predatory hellish warriors. Thus, most of the Bruxwar is populated by predators hunting for other predators. There are no herbivores, everything is either an omnivore or a carnivore. The vast majority of these animals are capable of flying, swimming, or burrowing, have extraordinary senses, and occasionally even abilities that replicate the effects of spells. Survival here is so difficult, that there's only one permanent settlement of humanoids on the whole island, simply called Bastion.
The Para-Elemental Plane of Ice has always been rather inhospitable. What made it worse was when a portion of it entered an Astral Plane bubble, which kept getting smaller and smaller until it enveloped only a thin layer of the skyland's atmosphere. Time ceases to flow for anyone who touches the island with a bare body part, and their body will slowly begin to freeze. Ice and snow eventually gather around the frozen body, until it completely becomes part of the island. This is why the skyland lacks any form of flora or fauna. Only flames created by sufficiently powerful magic can melt these bodies, which have been gathered here over the centuries.
It is unknown whether a small piece of wood from one of the elemental planes fell into a bubble of unfiltered positive energy from the Positive Energy Plane, or vice versa. What's known is that a tree has sprouted out of this destined meeting, and it keeps growing. While by now its growth is hardly noticeable on even a monthly basis, the truth is the skyland keeps getting bigger nonetheless. Sometimes, its branches twist in unpredictable ways, which is why flying creatures make up the majority of this land's population.
9. Skyland of Hats
The first impression that a visitor would have of this island is that it's populated by the undead and constructs. A closer look reveals that the vast majority of beings on this island wear a large variety of hats. The truth is, these hats are sentient and control any sufficiently humanoid bodies. On their own they can't do much, so they must rely on others to put them onto humanoid bodies such as corpses, skeletons, mannequins, statues, and other constructs. If two of these hats are close enough for an extended time duration, they produce a smaller offspring, that grows over the course of a year into a full hat. If living being dons (or is equipped with) this hat, it must resist its mental influence, or else be controlled by it (as per Ghost's possession).
The legendary empire of the elves ruled by the Shadow Queen floats through the sky is a constellation of incredibly tall spires, each overpopulated by the doorways to magnificent mansions that hold hundreds of elves each. Training, exercise, casting the spells, pledging allegiance to the Shadow Queen and to the Caretakers, ... Some may see this as a cycle, but it is a snowball, growing larger and larger the further it goes. It is the most dominant force of this realm and the major reason why most of the islands have elven populations on them.
Edit: Several days after publishing this article, I noticed that number 9 was not saved before publishing. I forgot what this island was, so I had to make up a new one.