The Cameo: Pluto makes a brief appearance in the Recess episode "Rainy Days".
He also makes an appearance in the Goofy short "Victory Vehicles", a Wartime Cartoon. This cartoon shows alternate modes of transportation (since gas and rubber were rationed). One vehicle is powered by a dog (hence, Pluto) that chases after a cat (a scraggly-looking Figaro), when it's put front of him.
Hypno Fool: Donald Duck hypnotizes Pluto into acting like a bunch of different animals on command in "The Eyes Have It".
Jerkass: It shows up, but not as much as in Donald.
Poorly Disguised Pilot: A year prior to Pluto getting his own individual shorts, one Silly Symphonies cartoon, "Mother Pluto", was centered entirely around him, having virtually nothing in common with the typical Silly Symphonies short.
Through a Face Full of Fur: In "The Army Mascot", Pluto turns green after swallowing a plug of chewing tobacco. He tries to swallow the green away, but it just comes back up. He then turns other colors as well, including, yes, plaid. Even his tongue!
In cartoons that are set in some snowy region, such as "Alpine Climbers" and "Mail Dog", there are instances when Pluto gets so cold he turns blue.
The Voiceless/The Speechless: Sans his sole words in "The Moose Hunt" and "Mickey Steps Out", unless you count barking as dog talk. Occasionally, he would make panting sounds that sound similar to "yeah, yeah!"
Hilariously lampshaded in the 50's-era MAD spoof "Mickey Rodent" in which Pluted Pup laments being the only animal in the Walt Dizzy universe who can't talk, by way of holding up signs.
White Gloves: Shown wearing them in the B&W cartoon, "Blue Rhythm."