Crashing Landing On You had Kim Soo-hyun cameo as a North Korean spy from his movie Secretly Greatly

There are a lot of fun individual cameos, but I'm having trouble thinking of a drama where there are a lot of them. Man to Man, perhaps? It has Song Joong-ki and Namgoong Min in fun scenes, so if you can get past how annoying the female lead is, that might be worth a shot!

Oh. Pop culture. But on the general side...

That would be Because This Life is My First's Lee Min-ki and Jung So-min cameoing as Mi-so's parents in What Wrong With Secretary Kim. That was another continuity of its own.

For the pop culture based/themed dramas, I think Jang Nara cameoed in the current running Cheer Up.
Shooting Stars ep 8 had Kim Dong-wook and Moon Ga-young cameoing not as themselves but as celebrities.

And there's House on Wheels. This one is a variety show but they have guests actors or actresses every weeks so they count as cameos?😁

Hospital Playlist 2 had a little stint with PD Na Young-seok but it lasted just 1 minute. HP 1 cameoed Go Ara as herself I think, cause there was a reference to her upcoming drama - Haechi.

For a drama with an real life actor meta reference, try Touch Your Heart/Sincerity of Heart. The FL is a celebrity actress in character. And 20th Century Boy and Girl. The FL is also a celebrity in character.

The Reply series do meta references the best like in Reply 1988, Lee Hye-ri parodied Lee Mi-yeon's Ghana chocolate CF, who played adult Duk-sun.

Record of Youth had quiet a few cameo, if I remember right. I remember PSJ and Hyeri but pretty sure there was more.

The Reply series is probably one of the best at meta references.

My favourite one is from Reply 1997. When Yoojung and Hakchan went on a date to the cinema to watch the movie Seventeen which stars a young Eun Jiwon (aka the actor who plays Hakchan). When Hakchan sees Eun Jiwon's terrible acting, he says "Even I can act better than that".

There were other jokes that poke fun at the fact that Hakchan is played by Eun Jiwon (member of popular 90s kpop group Sechs Kies). They were all gold.

In True Beauty, the PD used the actors of his precedent drama Extraordinary You as cameo : Kim Young-Dae came back as strawberry boy, Kim Hye-Yoon and Lee Jae-Wook came back as Danoh and Baek-Hyung, Jung Gun-Joo and Lee Tae-Ri as a student.

In Abyss, Seo In-Guk and Jung So-Min made a cameo as alien after their role in Hundred Million Stars From the Sky (the same PD).

In Vincenzo, Kim Sung-Cheol and Jin Sun-Kyu made a cameo because they acted with Song Joong-Ki in Arthdal Chronicles and Space Sweepers.

In Find Me in Your Memory, Kim Sun-Ho and Rowoon did a cameo because they knew Moon Ga-Young, they were playing a fake scandal :p

Shippers have backtracked to SECRET GARDEN for Son ye Jin's only cameo in HB's series.

Best Love
Hwayugi
Producers
King 2 Hearts
Scent of a Woman...

Seo In Guk as a sous chef in Oh My ghost
https://www.youtube.com/watch?v=iHyCw09ZPEU

what with the dramatic music and all

ah whoops I didnt catch that it had to be meta, I just thought you meant fast digesting

Be melodramatic for pop references from dramas, and PPL and I am sure they had some actors playing themselves for certain parts but I can’t name any.

The most hilarious a bit long cameo would be Jo jung seok in legend of the Blue Sea. Him and Jun Ji Hyun crying and pearls coming out from the eyes while watching sad movie.OMG! I can still recall this scene so vividly .

Next one is Moon Ga Young and Kim Dong Wook in Shooting stars, where they played the same characters in Find me in your memory.
I loved seeing them again <3

In Zombie detective, the rival private detective is played by the same actor that plays the characters played by Choi Jin Hyuk in The last emperess. Two times the rival private detective asks "Would I be like him if I loose weight?" (this is what happens in The last emperess I have read)
Comments speak of a Parasite reference, but I have not seen this movie so I did not catch it.

I was not able to recognise the cameo in Shooting stars, but I recognised several in Lovestruck in the city. (kept me alive, otherwise this drama is too boring)

Reply 1994, bus scene with cast of Reply 1997. Of the many meta references in the Reply series, that was my favorite. :)

My choice would be Sh**ting Stars. I remember seeing a lot of funny cameos though any references were lost on me.

A cameo that really startled me was Conan O’Brien in One More Happy Ending.

I definitely vote for Shooting Stars. They don't play themselves or former characters, but the cameos get to play other quirky characters. It must have been a lot of fun on set!

I loved Choi Ji Woo's cameo on Crash Landing on You. One of the north korean soldier ducklings was a huge kdrama fan and was especially a fan of Choi Ji Woo. The FL lead arranged a meeting for him to meet Choi Ji Woo. I think Netflix replaced the music, but originally, it had the iconic music theme from Stairway to Heaven. The whole scene was filmed like how it was filmed back then with the dramatic zoom ins and moving shots. And included some lines from the drama.

Also in Hotel del Luna, I loved Lee Junki's cameo where it looks like he stepped out of a scene from The Guest, which was a popular OCN series the year before. And IU and Lee Junki did Moon Lovers together. The FL is a fan of Baek Jong won so there were many references to him. Kim Soo-hyun, with whom IU also worked on two dramas with, also cameoed at the end, but I hated how his character changed the name and vibe of Hotel del Luna.

I remember seeing a drama where someone presented a clip of Ruler of Your Own World as a factual medical case study and said Go Bok Su made a complete recovery. I’m pretty sure it was recapped here but I’m fuzzy beyond that.

My Girl has a fun appearance by Han Chae Young and Jae Hee reprising their Delightful Girl roles.

Personal Taste, when Yoon Eun Hye appeared as Lee Min Ho's ex.

The Producers has a lot of meta going on - I don’t get all of them (and tbh don’t really like the drama) but did enjoy Lee Seung Gi’s cameo where he’s being super nice (as per his image) but gets hung up on the producer getting the name of his song ever so slightly wrong.

His cameo in Best Love/Greatest Love that someone else mentioned above is also great.

The cameos in Woohoo Waikiki were some of the best parts of the show - from Park Sung-Woong playing in several scenes without speaking a single line, to Kim Seo-Hyung almost killing Joon-Ki while method acting, to Lee Deok-hwa playing himself as the famous father of our struggling young actor character in the series.

In About Time, there was a scene where Lee Sang-yoon poured a drink and told Lee Sung-kyung that if he drank it, then they would be a couple. It was tongue-in-check but clearly a reference to that iconic scene in A Moment to Remember. I thought it was funny!

A recent example is Na In-woo in The Golden Spoon. Unlike many cameos, his cameo actually had significance to the plot.

Kim Soo-hyun had a cameo in Hotel Del Luna.

Gaus electronics was really heavy handed on all the recent popular shows in the last episode with the chaebol turned office intern trying to win over another office mate’s heart using all the famous one liners.

Goblin is a reference in almost every show I see. lol! Even the BL, To my star 2, has the male lead who goes to a local store and says: “I can buy everything from here to there on one card…”. Then asks the little girl he’s babysitting if she’s too young to know that reference. 😂 And Goblin itself also mentions Kim woo bin, won bin, and hyun bin as well as Park Bo gum.

Moonshine has lines from 2PM’s songs weaved into the script that Taec says. Hilarious. Actually, many idols in shows have metas to their bands/groups typically. Doojoon has a few (in the Lets Eat series and also Radio Romance). I have to say I’m proud of myself when I pick them up.

In Weightlifting Fairy, Lee Jun Suk makes a brief cameo appearance as a student athlete. He is a sharpshooter like his character in W. That was the first cameo I actually understood.

I can not add another show to the list others mentioned. However, Under the Queen's Umbrella ☔ had an unexpected camoe for me ... For a show like this I definitely was surprised to see Rain 😊

Among the dramas I have watched, I think that The Best Hit and Yumi's Cells (seasons 1 and 2) are the ones with more cameos or references to other dramas or pop culture.

Goblin was referenced in both of them.