Healer. No description is necessary. Just watch. You're welcome. 🥰

There are quite a few that I can think of. Listing in chronological order:

1. City Hunter
2. Healer
3. Descendants of the Sun
4. W: Two Worlds
5. What's Wrong with Secretary Kim
6. Vincenzo

To a lesser degree, shows like Hello Monster, Her Private Life, Hometown Cha-cha-cha also have uber-confident and competent heroes though the swagger is dialed down compared to the list above.

Hum...

Healer : everything was good in this one.
K2 : except the romance, it was a good action drama.
Heartless City : The best role for Jung Kyung-Ho!

Kim Sa-bu (Han Suk-kyu) in Romantic Doctor, Teacher Kim.

Ji Sung in "The Devil Judge". His role as a judge named Kang Yo Han who orders unprecedented punishments wouldn't have worked without him. He has a nuance for pulling off over the top scenes which would have been pretty laughable with any other actor.

No one swaggers like Special Labour Inspector Jo Jang-poong.

If i understand this completely, Happiness couple may fit the description. Saebom and Yihyun are both confident and competent in their fields. Even when they have zombies and devils in human form as their apartment neighbors, they are untouchable. Too good to be true.

Is Hwang Shimok a swagger? I don't know. But i think his inability to feel what normal people feel can be a huge advantage especially when you work with not so good people in your field. No one can intimidate and scared him. He wear suits daily and looks good in them. I think he is a swag

This gives me an opportunity I didn’t think would come and that is to say something nice about 2 dramas I refer to as recipients of my ‘Stinker of the Year” award and both unfortunately from 0CN: for 2021-DARK HOLE and 2022 (so far) A SUPERIOR DAY.
1. DARK HOLE. A bit like in HAPPINESS a man and a woman come together to become heroes in combating the zombie onslaught: Lee Joon-hyuk (1984) and Kim Ok-vin.
2. A SUPERIOR DAY. Jin Goo plays a firefighter who becomes a hero saving his daughter from a serial killer.
Both dramas are NOT recommended for viewing. Save your precious viewing time.

HEALER
HEALER
HEALER

Also Kang Chul in W - Two Worlds, but mostly:

HEALER.

Namgoong Min's character in Hot Stove League.
It's rare to have a character that you trust.

Definitely gotta be Vincenzo Cassano/Quassano, mafia Corn Salad extraordinaire.

Kim Young-kwang in Lookout
Jun-ho in Chief Kim
Kim Nam-gil in Through the Darknes
Ji Sung in Devil Judge
Cha Seung-won in City Hall
Park Seo-joon in What's Wrong with Secretary Kim
Yoo Jae-myung in Forest of Secrets
Joo Ji-hoon in Hyena
Kim Soo-ro in God of Study
Jung Kyung-ho in Falling for Innocence
Lee Seung-gi in Hwayugi
Lee Jung-suk in W
And I know this is VERY random, and he has a small role, but Lee Moo-sang in What's Up? has THE swagger!

I can go on forever! 😂
I wish I had the presence of mind to remember them all immediately.

The Spies Who Loved Me : More of Derek Hyun and less of Jun Ji-hoon.
The Devil's Judge : Kim Minjung and Ji Sung
More recently Bloody Heart.
Life : Cho Seung-woo.
Forest of Secrets.
Juvenile Justice.
Beauty Inside[Drama].

In the swagger/confidence and scheming department, I think the duo of Namgoong Min and Jun-ho in CHIEF KIM were perfect foils for each other to enhance each other characters.

Fiery Priest and My Strange Hero aka revenge is back

The ultimate hero of swag is Son Oh-goong from Hwayugi. Nothing builds confidence like immortality and the literal power to overturn mountains.

But also Healer, W, My Love From the Stars, Goblin, Vincenzo sports good examples.

Happiness
The Fiery Priest
Terius Behind Me
Rebel
Black

IU in Hotel Del Luna.

I have a soft spot for anti-heroes and these are my top 3:
Chuno
Punch
Nirvana in Fire

I forgot to mention, Yang Yang's character Xiao Nai in the C-drama Love O2O surely qualifies. What prevents him from becoming boring is that the FL (Bei Weiwei, played by Zheng Shuang) is also very competent, and not without swagger of her own.

I think this type of hero makes a bad drama worse, Exhibit A being Well-Intended Love, which I wouldn't recommend to anyone.

I’m guessing ‘larger than life’ means ‘cool & charismatic’ and not ‘weird & quirky’

Kang Ji-Gu in Work Later, Drink Now
Song Ji-Won in Hello, My Twenties! S1&2
Ra Mi-Ran & Jung-Hwan in Reply 1988
Do Soo-Hyeok & Jo Ki-Bbeum in Sh**ting Stars
Jo Min-Ja in Healer
(honestly any role that Kim Mi-Kyung plays, she has a magnetic presence and always manages to give a nuanced performance to some otherwise flat characters)
Sim Myung-Yeo & Sim Myung-Joo in When The Weather Is Fine
(I know tragedy doesn’t make someone interesting but gosh darn, did I FEEL for these characters, the amount of love, hurt & guilt they felt for each other just gutted me)

Characters that THINK they are cool & charismatic

Hwang Tae-Kyeong in You’re Beautiful
Dok Ko-Jin in The Greatest Love
Kim Sung-Kyun in Reply 1988 ( the character with the most dad jokes but still the most lovable!)

Has anyone mentioned KIM SHIN in Goblin/Guardian? Just me? Gong Yoo wins the swagger award hands down, every freaking time.

GOBLIN: THE GREAT AND LONELY GOD is definitely one such show.

I would add MY SECRET TERRIUS as well.

I would say Chief Kim. He came in as some random accountant who used to cook the books for gangsters. He was a self-interested individual meant to be a cog in the corporate machine, but he went onto fighting the corporation and turned the CEO's spoiled sun and our villainous executive, Seo Yul, onto his team. He even made a fan of the woman wiretapping him.