-This page by Voyd
Trox are a burly race of subterranean beetle-men that have the distinction of being the only 0HD race that's Large. They're best suited to martial roles, but it's possible to finagle them into other classes, including a few spellcasting classes.
Ability Scores: Trox get an absolutely monstrous +6 bonus to Strength, meaning that they're at their best in melee combat. Now what's the downside? A -2 to ALL of their mental scores, and their size also means they have a hidden -2 to Dexterity. However, the mental penalties can be offset by the Strength bonus, even for a few spellcasters.
Size: Trox are the only Large race, meaning that they have long natural reach, a bonus to their combat maneuvers, and an already-factored bonus to Strength. There are downsides, though: A trox is never going to be sneaky, and they also have a penalty to their AC, so they're a bit easier to hit than most characters.
Type: Trox are... well, it's inconsistent. The Bestiary entry says that they're monstrous humanoids, but the "monsters by type" list places them under humanoids. Better get your GM's opinion on this, though I'm pretty sure they're supposed to be the former. If that's the case, then they can't be enlarged, but since they're big fellows already, do you really need enlargement?
Frenzy: You get a pseudo-rage! It's only useable once per day, but here's how to rage as a lawful character.
Grabbing Appendages: Hey, it's a race built for wrestling! You get Improved Grapple, and the best part is that you can maintain a grapple and still attack other creatures. Very nice!
Alchemist: Even with an Intelligence penalty, a trox can make for a very nasty mutagen-based alchemist. ALL THE STRENGTH BONUSES!
Barbarian: It's obvious that this is the role that trox were meant to play, as the sample character in Bestiary 4 is a barbarian, and they also have a racial pseudo-rage anyway that stacks with rage. Multiclass into alchemist to snag a mutagen and you become a melee nuke.
Bard: Penalties to Intelligence, Dexterity and Charisma means that trox are never going to be good at performing.
Cavalier: I don't think the APG writers anticipated a Large race. What sort of gigantic mount would a trox use, anyway? An elephant? If anything, I'd house-rule that trox can't take the Mammoth Rider prestige class, since they'd need a Huge mount to support their weight anyway.
Cleric: Why are you playing a full spellcaster as a trox? If you want to cast spells, go with the alchemist.
Druid: I repeat.