Gooh my glob! One of my favorite Japanese directors Masaaki Yuasa has written and directed an episode of Adventure Time http://www.dorkly.com/article/61961/japan-is-making-an-episode-of-adventure-timejapan-is-making-an-episode-of-adventure-time
Did Season 1 have previews? I am not sure. I cannot find any previews for Season 1 episodes.
Season 2 had that promo with the live action sword.
Season 3 had episodic promos, general Cartoon Network stuff though.
Jake vs. Me-Mow
Season 4 had this one
with the exception of Burning Low, which had this misleading one.
The whole of Season 5 had this promo below.
Season 6 now has this one:
It’s evolved from our goofy main logo into this beautiful thing.
this pigeon was having trouble pecking at a stale cookie on the street so i went over and crushed it with my foot so it could eat better and i think that was the nicest thing i did this year
FUCK YOU GUYS WHO THOUGHT THAT I CRUSHED THE PIGEON AT FIRST IM A NICE PERSON