Check out Babylon 5, telepaths are a major part of the story for so many reasons.

Lots of psychics in Star Trek. Vulcans, Betazoids, and Ocampa for instance.

I feel like there are some in The Culture series but its been a minute since I read them and I only got a few books in.

Dune has a lot of kinda-psychics. Paul and pretty much all the Atreides after him would count i think.

There are some in the Foundation series I believe

Starship Troopers had Neal Patrick Harris read a bug's mind

Just about anything that's not especially "hard" sci-fi tends to have psychics of one sort or another. I dont remember any psychics in The Expanse or BattleTech but my knowledge of both is rather limited edit BattleTech no, The Expanse yes from a cursory search

Also how was OP's 40k xeno example orks and not Eldar ;D orks are way cooler and more fun i agree tho

Not sure why you're asking for the most popular...

But Stranger in a Strange Land eventually gets around to that.

It's about a human raised by Martians, and he learned a Martian telepathic language that can alter reality. But when returned to Earth, he has no idea how humans act, and is basically an infant.

But it's one of those books that changes a lot,bthe begining isn't what you're looking for, but just stick with it.

I don't know about popular, but one of my favorite examples is Sid Meier's Alpha Centauri. It's an old game (1999) but I'll put the psionic stuff in a spoiler tag because, If you like Civilization type games and want a good story, I think it's worth going in blind and experiencing the story as it was intended.

I distinctly remember having my mind blown as the story unfolded. It's been many years since I've thought about it; gonna have to dig it up and see if it's as good as I remember it :)

WandaVision: She creates a new reality around herself.

Fringe: One of the main plot points are psychics controlling reality.

Push: A movie about a psychic people that can push thoughts into other people’s heads.

Legion: Mind bendy reality show where the main character can control reality.

Might not be relatively popular, but the psionics of the novel/anime Shin Sekai Yori are central to the plot and are portrayed in a pretty interesting fashion.

Foundation is another (more traditional sci-fi) work which also focuses on psychic people as a central plot point. The book series and TV series are very different, but I'd say each explores the idea well.

For video games, Control is another one I haven't seen mentioned yet. It's based on the SCP collaborative fiction project. Exposure to objects of power awaken the protagonist's (and other characters') latent psychic abilities.

Psionics was more popular in older sci fi, a few that come to mind are:

• The Lensman series - one of the classics in sci fi, mental powers are very prominent.
• The Tower and Hive series (also Dragonriders of Pern by the same author to a lesser extent as it's largely just telepathy in that series).
• The Saga of Pliocene Exile series.

Read stuff written before the turn of the millennium if you're into this, I feel like it's become less and less common in sci fi as time progresses. I guess it's because mental powers - being effectively magic rather than technology - slot better into fantasy than sci fi in modern readers expectations.

dune, foundation, starship troopers, stranger in a strange land, martian chronicles, its fairly common in a lot of classic scifi as some sort of evolution things that happens. even 2001. Sometimes its hard to identify if there are psychic abilities or technology that is allowing for the abilities.

The Protoss from StarCraft.

Uh, also the Terrans to a limited degree.

Judge Anderson in Dredd had the ability to read thoughts and create illusions of the mind.

Akira is an all time classic

You can find the Kronenburg movie Scanners on Archive.org

Akira is another big one.

Names of some of the stuff are Telekinesis, Pyrokinesis (and Cryokinesis), Psychokinesis, Precognition, Postcognition, Astral Projection, and that one word for finding lost objects or dead bodies I forget. And sometimes Empathy.

EDIT: Dowsing!

oh forgot babylon5. its a major part of the world.

I like the psionics (or well Psycasts) in rimworld and it has a prominent enough role.

Mind tech that calls some machine superintelligence to alter reality, bestowed by space feudalism.

In the book chysalids the main characters are psychics and can draw shapes and emotions In their minds and it broadcasts out for miles and can be picked up by others like them. They all communicate on a global channel and have to conceal it from the humans who are deeply distrusting of anything different.

How about something like the movie Dark City ?

Starcraft had the Ghosts.

That may be based on something in Warhammer 40k, which you already mentioned, as I understand that some elements of the game were based on Warhammer 40k. I'm not really super-familiar with the lore of the two enough to know, myself.

Dune has lucid "prophets" (the guild navigators, Paul and Leto II, for example), and Paul can even see/feel his way around the world through his prophetic visions when he loses his sight in Messiah. "The voice" is described almost as an advanced technique that is purely physical and psychological and not magical so idk if it fits.

Firestarter with Drew Barrymore is a movie with pyrokinesis.

Also, I don't see a lot of books in here, but Alan Deal Foster's Flinx series is about a telepath.

Not entirely sure how close this hits, it's been awhile since I played through the games, but I think System Shock 1 & 2 as well as Prey lean into the psionics quite a bit. I think that's how the powers are derived, one of the enemies in System Shock 2 are experimental monkeys with psionic powers that shoot fireballs at you. Hate those little guys, every time I hear their chatter I get a bit on edge.

I can't remember the exact examples, but Farscape had a decent few in it.

The Scanners movies. Just watch the first one though.

i just finished a 3 book series by Adrian Tchaikovsky called The Final Atchitecture. it features several characters with this ability. i highly recommend it!

IMHO the funniest one was Ghostbusters: they think about an arbitrary monster and it appears in the next second, but super sized.

Other nice movies: X-Men, Lucy, Sphere, Solaris, Matrix

Scanners

https://www.goodreads.com/series/49441-the-talents-universe

The talents books by Anne McCaffrey

The sci-fi book series "Perry Rhodan" features a lot of humans and other beings with all kind psionic powers.

Telepathy, telekinesis, invisibility, teleportation, fire, ice, atomic restructuring, the list is really really long.

Firestarter

"More Than Human" by Theodore Sturgeon is a novel about a collective of psionic humans who have to work together because they have an unusual mix of powers and weaknesses. One of them is a forever-infant whose role is a living supercomputer, for example

"Ishmael" by Daniel Quinn is a bit of a stretch, but it's technically a conversation between the main character and a telepathic gorilla, if you want something a little different than the usual story about psychic humans

On the movie side, there's "Beyond the Black Rainbow," a somewhat trippy thriller and sort-of horror story about a psychic adolescent girl being raised by a scientist who developed a disturbing obsession with her. Might be a little rough to watch on that note, but it's good. I liked the way they portrayed how her powers worked and it was an interesting audio-visual experience besides

Its hard to say what the most popular are.

Star Wars is sorta explicitly not psionics, the force is an outside thing that force users can tap into.

Mass effect has psionics, but psionics in general play a really minor role, some psionic characters play big roles, but them being psionic is meh.

Warhammer 40K might be the most popular franchise where psionics plays a major role. Every major faction except the Necrons are defined/driven by their psionics.

Star Trek has some psionics, but those are generally minor plot points, not major ones.

Dune has the Atreides be psionic, the Bene-Gesserit are arguably psionic, as are the navigators.

Akira is all about psionics, and is arguably Sci-Fi, if a grittier, closer to current reality one.

Arguably the most popular series with psionics is Star Trek.

Arguably the most popular series where psionics plays a large role is either Dune or Warhammer 40K. Warhammer 40K has probably made more money, but I think more people have read Dune.

Two video games got me kinda obsessed with psionics as a younger person:

Psi-Ops: The Mindgate Conspiracy. It's a near-future military thriller where the main character has amnesia, but finds himself with telekinesis, pyrokinesis, remote viewing, mind control, and "mind drain" to power those abilities. That game was amazingly cool and had a banger single called "With My Mind" by Cold (https://www.youtube.com/watch?v=-ZQk3ig-i_s)

It's been a long time, but our guy basically battles a rogue paramilitary bad guy faction that's like "If MK ULTRA actually worked on a few dudes and they were super fascist."

Second Sight: Still gotta play this one! Kinda like Bourne Identity. Guy wakes up in a strange facility with psychokinetic powers and amnesia, and strange government people are trying to kill him. He can throw things around with his mind.

(I feel like these were the same game pitched to two different publishers hahaha)

Hehe I remember really trying to exercise my mind to put out matches or move objects. Was quite disappointed. :p

Chronicle: This one is an interesting movie. Kinda a found footage superhero film. Three friends touch a weird rock and end up with telekinesis. Things kinda derail out of control from there. Excellent effects.

(Somebody already mentioned "Push" which is also super cool.)

Peter F. Hamilton's Greg Mandel trilogy - the titular character is a former psi-soldier turned mercenary. IIRC, candidate psi-soldiers are given a brain implant that squirts out psi juice on demand, and each soldier develops unique and unpredictable powers. Greg's was the ability to sense, control, or kill other nearby minds.

Surprised no one has mentioned Stranger Things.