I am looking to create a campaign set in space, with lasers, spaceships, Jedi, and other such things. I am bubbling with ideas, but when it comes to aliens, I have hit a roadblock.  Any ideas for original aliens, reskinned dnd races, or even reskinned races from any other franchise would be greatly appreciated.

Well if you are going to reskin things, I would think Asari (Mass Effect) would work as reskinned elves. Their natural tendency toward "biotics" would work as the elves' natural tendency toward magic.

If you are doing Star Wars (you mentioned Jedi), Jawas as reskinned kobolds perhaps.

• Vulcans=High Elves
• Romulans=Drow
• Andorians=Dwarves
• Klingons=Orcs
• Ferengi=Goblins
• Cardasians=Hobgoblins
• Bajorins=Gnomes

Just a few off the top of my head.

Are you looking for more boring, staple aliens that you can easily adapt from 5e races, or are you looking for more original things? I’ve got both, just let me know.

Either one. Both. Honestly, I will take anything at this point.

An apelike species, similar to humans, but a bit more similar to gorillas than to chimpanzees. They’ve developed a symbiotic relationship with a very efficient, barklike black plant that covers their skin. The plant provides them with nutrients and protection, while leeching water from them.

For stats, I’d give them +2 con, +1 wis. They wouldn’t have to eat when in a sunny environment, but they’d have to drink twice as much. They would also get natural armor, and would have both plant and humanoid as their creature type. And then maybe one other ability.

A species that long ago learned how to digitize consciousness, allowing them to place their minds into robotic bodies, and become effectively immortal, as long as they had a backup. For balance reasons, their homeworld, and the location of all the aforementioned backups, was recently destroyed. If their memory chip can be saved when they die, they can still be downloaded into a new body, but they are no longer immortal, just less mortal than most.

I’d just make them warforged, preferably the old ones because the new ones are garbage.

I’ve got more, but I’m tired and sleepy so meh imma sleep instead of writing them out.

To make aliens, I think most of the Eldrazi modification options could be added to make Aliens.

Quote from Plane Shift Zendikar

• Eldrazi are immune to psychic damage and the charmed condition.

• Eldrazi of Ulamog’s brood lineage have no eyes; they are immune to the blinded condition and have blindsight to a range of 30 feet.

• Some drones act as extensions of the Eldrazi titans’ hunger. Change the damage type of such a monster’s attacks to necrotic damage.

• Some Eldrazi have a Life Drain ability similar to that of a wight, forcing a target to succeed on a Constitution saving throw or have its hit point maximum reduced by an amount equal to the damage taken. This reduction lasts until the target finishes a long rest. The target dies and is utterly consumed by the Eldrazi if this effect reduces its hit point maximum to 0.

• Some Eldrazi are responsible for the creation of new spawn. Such a drone might have an ability akin to the red slaad’s claw attack, implanting a nascent Eldrazi spawn in the host’s body.

• More powerful Eldrazi can consume spawn and use them as fuel for their own abilities. The Eldrazi destroys an Eldrazi spawn within 5 feet of it and either regains 10 hit points or regains the use of a single ability as though it had finished a long rest.

 I'm not quite sure what the Eldrazi are, but these seem like alien characteristics.

Aberrations of all types make excellent alien creatures.  That's largely the purpose of the creature type.

Keep all the current races and monsters and just inject them into the space age. Easy and done.

Quote from Margaret22 >>

To make aliens, I think most of the Eldrazi modification options could be added to make Aliens.

Quote from Plane Shift Zendikar

• Eldrazi are immune to psychic damage and the charmed condition.

• Eldrazi of Ulamog’s brood lineage have no eyes; they are immune to the blinded condition and have blindsight to a range of 30 feet.

• Some drones act as extensions of the Eldrazi titans’ hunger. Change the damage type of such a monster’s attacks to necrotic damage.

• Some Eldrazi have a Life Drain ability similar to that of a wight, forcing a target to succeed on a Constitution saving throw or have its hit point maximum reduced by an amount equal to the damage taken. This reduction lasts until the target finishes a long rest. The target dies and is utterly consumed by the Eldrazi if this effect reduces its hit point maximum to 0.

• Some Eldrazi are responsible for the creation of new spawn. Such a drone might have an ability akin to the red slaad’s claw attack, implanting a nascent Eldrazi spawn in the host’s body.

• More powerful Eldrazi can consume spawn and use them as fuel for their own abilities. The Eldrazi destroys an Eldrazi spawn within 5 feet of it and either regains 10 hit points or regains the use of a single ability as though it had finished a long rest.

 I'm not quite sure what the Eldrazi are, but these seem like alien characteristics.

 Eldrazi are a M:tG creature that was added to D&D rules when they released Plane Shift: Zendikar. They are basically cthulhu-inspired world eating abominations. 

In my mind, there really is only one truly alien culture:  Hive Mind.

Anything else basically has the same kind of restrictions humans do.  Oh, sure each will have certain concentrations - racist vs.  money vs war vs study etc. etc.   But the only creature that truly will not be understood by us and vice versa would be a creature that had no social activity at all because it was just a single mind.

So I would personally have the big bad, no treaty, no quarter, no understanding, be a Hive mind of some kind.   Whether you call it The Borg, or The Insects,  or something else, a hive mind is the most alien race humans have imagined.

Besides Modrons, the Kruthik from Mord's Tome of Foes makes for a great Hive mind. I like the fact that they use constructs, undead and oozes.

Quote from Mog_Dracov >>

In my mind, there really is only one truly alien culture:  Hive Mind.

Anything else basically has the same kind of restrictions humans do.  Oh, sure each will have certain concentrations - racist vs.  money vs war vs study etc. etc.   But the only creature that truly will not be understood by us and vice versa would be a creature that had no social activity at all because it was just a single mind.

So I would personally have the big bad, no treaty, no quarter, no understanding, be a Hive mind of some kind.   Whether you call it The Borg, or The Insects,  or something else, a hive mind is the most alien race humans have imagined.

 Aren't hive minds as the main villains a little overused?

Yes, unless you do it in a unique way. Take the Formics from the Ender’s Game books. I won’t spoil anything for those who haven’t read the series, but they aren’t what they seemed to be.

Quote from WoobyDoobyDoo >>

Yes, unless you do it in a unique way. Take the Formics from the Ender’s Game books. I won’t spoil anything for those who haven’t read the series, but they aren’t what they seemed to be.

 Exactly.

Hive Minds are overused.  Because anything else is not truly alien. Non-hive creatures are almost always easy to understand - unless the author cheats and does not build them a logical culture and simply says "they are alien so you don't understand them."

Oh, your klingons are violent but honorable?  Kind of like Kizinti?  and a third of all other 'evil races'?   

Quote from Mog_Dracov >>

Hive Minds are overused.  Because anything else is not truly alien. Non-hive creatures are almost always easy to understand - unless the author cheats and does not build them a logical culture and simply says "they are alien so you don't understand them."

Oh, your klingons are violent but honorable?  Kind of like Kizinti?  and a third of all other 'evil races'?   

 What's wrong with having an alien species that's similar to humans? Not every species needs to be unique. It's actually more realistic to have alien cultures similar in many ways to human culture. And there should never be any sort of generalization like "these guys are the bad guys", "this is the species that's violent but honorable", etc. Every single species will have its different cultures within itself. While they might be united under one flag, or whatever, they're still all different, all unique. You simply can't lump them all into one category. And there are plenty of things beyond hive minds that are "alien". Just because you can't conceive of one does not mean it exists. And a species doesn't have to be different because of its physical traits, it can be alien just because their cultures have been shaped by the world around them. A tiny change can send a species going in a completely different direction from humans, even if they are otherwise identical.

The reason aliens tend to be based on human cultures is because writers are generally human and it's hard to really, truly get into a completely inhuman mindset when writing.

And even if you succeed in doing so, it prevents your alien species from actually being able to meaningfully interact with humanity- if their minds are incomprehensible and inscrutable, their actions will be as well.  That's fine if all you want to do is have a bug war, but you can't really have them sit down and do anything with humanity that requires communication.