As far as archetypes go... I'm not sure you could really call them 'good'. The line between an archetype and a steryotype is dangerously thin - the use of girly archetypes in the show could be seen as a Deconstruction, in a way, in that the point of using them was to show, A), there's lots of ways to be a girl, and B) Girls
aren't definied by specific traits. There isn't 'the tomboy' and 'the fashinista'; girls are like boys in that they're defined by a multitude of traits and are far deeper than the cliches one assumes.
An archetype is usually a shorthand for a character, a way to give the audience context to build on, or assumptions for the writer to break down - assumptions made about Rarity as 'the girly girl', for example, have been smashed straight to bits over the course of the series.
To use a more in depth example(Because I made it, shill shill shill) in Ask Hoops and Dumbbell, Dumbbell is a common gay archetype(Or rather, a few kinda melded together). He about 15% gym bunny, 60%
Manly Gay and 25% low-self-esteem gay. Gym Bunny and
Manly Gay come about largely through his character in the show proper, so there's not much to explain there - although I do use it to draw a contrast with the much more mellow Hoops largely for the sake of their relationship dynamic - but the self-hating,
Armoured Closet Gay elements are done deliberately to give rise to multiple issues, namely confronting the way that society contrasts homosexuality with what's deemed traditionally masculine. Though Dumbbell is by far the more traditionally masculine of the two, the apparantly dominant personality in the relationship and(Spoilered for TMI)
Far more likely to initiate sexual encounters normally, He's still
The bottom, and actually enjoys being led about in bed.
The point there was to have him simultaniously fill the 'man' and 'woman' roles in the relationship, to show that the idea of genders rolls in a relationship are inherently false. I used the archetype as a deconstruction of a perception.
Of course, you probably understand all that on some level and were just looking for the basic archeptypes to play off of... but good things to keep in mind regardless. For Archetypes I can suggest the
Strong Silent Type, especially emotional at the core(Think Big Mac), a Class Clown type(Imagine Pinkie but as a dude and everything that comes with testosterone), and The Hockey Kid(Which may be a personal archetype from my own experiences, but in general the hockey kid is brash and confrontational, but good-naturedly so. As in Hockey, a fight is just a thing that happens and you get over it and go back to 'fair' play afterwords. Usually.)