This is quite the funny coincidence, I had been intending on doing an Adventure Time on september for months, as it'll mark the 5th anniversary of the original show's conclussion, but as it turns out, the show has just gotten revived, so it's perfect timing anyway.

So, the idea of this batch will be to basically either turn characters of your choice (or even yourself) into Adventure Time characters, or simply get artwork of Adventure Time characters in any context of your choice.
There's plenty of characters to choose from, aside from the standard most famous ones like Finn, Marceline, Bonnibel, Fionna or Flame Princess. There's many many many many more characters in the show, such as Betty, Canyon, Jake, Huntress Wizard, BMO, Breakfast Princess, Susan Strong and many more you can choose from. If you haven't watched the show you simply can dive into the wiki for a while and you're bound to come across a character design you're fond of.

I've drawn Adventure Time pictures multiple times, you can see examples here:

Gym Bully
Very Vampiric Victory
Come Along With Me
I wish I could help you, except I don't!
Princess BubbleButt Returns
Flaming Smoky Taste
To a Cliff Under a Tree

And plenty more examples you can see here

As mentioned above, you can go with having a character of yours or maybe from an existing franchise either transforming or cosplaying as an Adventure Time character, or simply get artwork of Adventure Time character, as I've drawn them before, can be a normal version, fat version, age regressed version, nerdified version, impified version, etc. etc. etc. NSFW is fine too.
You can also combine or redesign outfits, have them wear different things, etc.