Thinking about how I would interpret the various people from the Dream smp winning the elytra contest:
Tubbo: Built the wings himself. They have a certain steampunk vibe to them. Really bulky, but also really cool looking.
Tommy: Moth wings. Screw everyone who says otherwise, man is a moth hybrid. But, well, insect wings are very fragile and he’s never felt safe enough to use them until now.
Ranboo: Recently received a gift from the council. It's a rare item that can be found only in the end. They hope it'll help him remember, it probably won't.
Georgenotfound: Got gifted some wings from DreamXD. He is not sure why or when, and he's not even entirely certain they're real. He may simply still be dreaming...
Sapnap: Lava wings. They're very droopy. He hasn't been maintaining them too well, and only recently got back into taking the lava baths he needs for them regularly.
Sam: He also built his own wings. They're lava-powered and look as if they were made of obsidian. They were initially meant to be part of the guard's uniform for the prison but... well. He's the only one working there, isn't he?
Ponk: Stitched them onto themselves as a medical experiment. They don't know how to take them off now, but they seem to work?
Bad: Huge af demon wings. He's 9'6 so his wings actually have to be enormous. Only reason why he hasn't used them before is that he was afraid to hit someone with them. Turns out he does that anyway even without using them, so there's really no reason anymore.
Fundy: The bird genes from his grandpa are finally manifesting. Perhaps biology does make some sense on the smp finally!
Wilbur: Pretty sure that's just a piece of the void sticking to him. Straight up ripped a piece of Limbo and brought it with him when he came back. Just another thing he hates about himself.
Punz: He knew someone high up who owed him a favor. Don't ask.
Purpled: Alien tech! He couldn't repair his ufo entirely, and those are his best bet to get off-server while he's working on his new one. They're meant to be a temporary solution, but they're pretty cool.
Eret: Flamingo wings. Ngl, they sort of forgot they had them.
Jack Manifold: similar to Wilbur's situation, but Jack's wings are very glitched. He was too afraid to die again to try and use them, but he's got to a point now where he doesn't care too much if that actually happens.
Niki: Hand-sewn wings that she made herself. It took ages for her to find a way to make them work, but having something like that to busy herself turned out to be really rewarding.
Quackity: He's a shapeshifter. He decided to change up his features a bit. Maybe he's getting ready for a fight he's certain will happen soon, who knows...
Karl Jacobs: Acquired them at some point during his travels. Much like George he's not sure how, when, or why that happened, but he's not complaining
HBomb: The power of anime bestowed them upon him. He did a full magical girl transformation and now they're there
Techno: Crafted them himself. They're not a marvel of engineering like they would be if Tubbo or Sam created them, but more so the result of months of him studying magic and alchemy for it. They were initially meant for Phil, but he screwed up the incantation.
Phil: They're prosthetics. He had to wait a long time for them because wing prosthetics are quite an expensive and complicated thing to obtain, but finally, he has them.
Ant: There's a whole lot of myths about cats with bird wings, so I'd say Ant finally ascended to his ultimate form of big ass cat with bog ass eagle wings.
Puffy: Went on an adventure after years of not sailing the sea and found an incredible treasure. She's pirating again and it's paying off, good for her honestly.
Foolish: Totems naturally have wings. He only stopped using them as a sign of respect for the rules of the server, but he's been shackled long enough now, wouldn't you say?
Hannah: Wings of thorny vines sprouted from her back as she started healing from the Egg's influence and reconnecting with nature.
Eryn: They just had them. They're probably an avian and we just didn't know yet.
Michael: Similarly to Eryn, he's just a winged hybrid.
Slimecicle: Well, once upon a time a little slime evolved in the course of thousands of years to become a human... what do you mean humans don't have wings? Oh well... he likes them now... maybe we can make an exception for him?