My Little Steampunk Dentist
What is she doing I have no idea. Apparently heading somewhere on her, uh, toothpaste-powered toothpaste surfboard tube.

But. Colgate is one of my most favourite background ponies. I like to think of her as a jolly, energentic and a bit crazy pony.
And screw blindbags, her name is NOT Minuette! (how is this even supposed to be pronounced?)

And I like her even more since I played "Minty fresh adventure" game. [link]
If you didn't play it yet do it. It's awesome.
(and you can even meet Doctor Whooves!)
Other Steampunk Ponies:
The Inventor — Twilight Sparkle >>3872
The Timid — Fluttershy >>3855
The Mechanic — Applejack >>75758
The Pilot — Rainbow Dash >>2536
The Random — Pinkie Pie >>2541
The Lady — Rarity >>3687
The Dentist — Colgate >>Here
The Princesses — Celestia and Nightmare Moon >>3972
The Flyers — Spitfire and Soarin' >>4758
The Smuggler — Carrot Top >>19100
The Messenger — Derpy Hooves >>34431
The Dreamer — Lyra >>46445
The Professor — Cheerilee >>47442
The Virtuoso — Octavia >>48717
The Evil Queen — Chrysalis >>50247
The DJ — Vinyl Scratch >>51412
The Soldier — Big Macintosh >>57995
The Illusionist — Trixie >>74358