I've been watching Ma Boy lately & right now I'm finishing Adolescent Medley and liked the idea of a mini dramas like these one. 

I was wondering if there was any others mini dramas you knew, or just a small dramas, like 12 episode or less. 

I'm fine with anything, it just need some romance into it.

Oh and I'm fine with any language, it doesn't have to be korean.

Thanks you x)

I haven't seen any of the following dramas, but these are some minidramas that i know of and that cought my eye:
After school: Lucky or not
Another Parting
Twenty years old
(exo next door could be also considered as a mini drama?)
(The lover is not a drama that i see as a minidrama but has 12 episodes and it is funny af. and has some realistic romance ;))
Be Arrogant
Exo Next Door (though there are 16 episodes but they're barely 15 min)
Dream Knight
Momo
Love Cells
After School: Lucky or not
Another Parting
Secret Love
Aftermath
We Broke Up
Dr. Ian
Coffee ya no Hitobito is a really nice slice of life drama with 5 episodes. :)
Thanks you very much guys ! There's some pretty good recommendation here. I probably will start with Twenty years old seems it seems the most interesting for me then watch the rest. Thanks again !
Himitsu no Kankei ~Sensei wa Doukyonin~
Juunen Saki mo Kimi ni Koishite
Heartbeat Love
Prince's Prince

... and you'll probably enjoy After School: Lucky or Not and Aftermath too ;)
I second Sirius.
I also loved White Christmas. It is my favorite drama of all time.
I've only watched one mini drama that I liked so far which is "Never Give Up, Dodo" it's a Chinese web/mini series and it  was so much fun to watch despite its ridiculousness :)
Vampire Flower & I Order You
If you're fine with any language, you should watch japanese dramas. They nearly always have about 10 episodes.
I can recommand some I rated 9 or 10.

Police / mystery genre :
- Guilty Akuma to Keiyakushita Onna
- Remote
- One Missed Call
- You're under arrest

Romance :
- Kekkon Dekinai Otoko
- Kimi wa Petto

School :
- Glass Mask
- GTO (1998)

Oh, I also remember 2 korean web dramas. Short episodes but well-done. The first one is Aftermath, I found the videos on youtube. The second one is After School :  Lucky or Not. But I don"t remember where I found it.
Thanks you very much ! I have a lot of dramas to add to my list now xD 
I'll probably start After School :  Lucky or Not next, It look so interesting.
I have already watched many mini dramas and one or two episodes specials.
Can someone recommend new ones?
Splash Splash Love
Page Turner
Monstar 
High End Crush
Goho's Starry Night (This and High End Crush have over 12 episodes, but the length of the episodes are about 15 mins)
Page Turner (This one is AMAZING! Although it's not full on romance, it has a romantic subtext and tension between the characters)
Thumping Spike (Also has over 12 episodes, but is short in length)
Bong Soon - a Cyborg in Love