Other than the four found in the We Be Goblins series, are there any pregenerated Pathfinder goblin PCs out there? Ideally I'm looking for a similar format to the WBG pregens: stats, a small character introduction, and a goofy song.
Take a look at Bloodmoon Goblins by John Grana of Fear The Boot.
Goblin PC rules as well as a complete "clan" with detailed character studies.
Good fantasy requires the heroic triumph of an underdog. So give your players some rotting leather armor and chipped daggers, and make them fight enemies twice their size who know how to forge steel and read scrolls. Give them Bloodmoon Goblins.
The orignal starts out with Fighter, Alchemist, Cleric and Rogue; all come with a little introduction, songs, and detail rich, silly inventories, including for example a "flask of human perfume (half drunk)". Where can you find more
- There is a completely free set of 3 alternate characters for We Be Goblins: a sorcerer, ranger, and bard (archeologist). It includes character introductions, songs, and inventories (including lucky toads with names), and even drawings (though in grey-scale). Further it makes suggestions for how to modify the module to challenge more than 4 players. -- These characters are balanced, as the original 4 use 15 point buy, and these three have only 14, 11, and 14 respectively.
- Here free a witch and a barbarian, with wonderfully silly inventories, colored illustrations (though in slightly different style from the module) and with songs and with point buy values of 13 and 15.
- There's another free set of 2, a barbarian and ranger, with song and some silly inventory items, but without story or image and seriously overpowered with their point buy values at 30 and 23 respectively. Also less importantly the barbarian's name and song reference stabbing while his only weapon seems to be a Warhammer. -- I went ahead and converted to standard buy attributes that you can use: Str 13 (+1) Dex 17 (+3) Con 14 (+2) Int 8 (-1) Wis 12 (+1) Cha 8 (-1), and Str 12 (+1) DEX 18 (+4) CON 12 (+1) INT 10 (+0) WIS 14 (+2) CHA 6 (-2).
- Here ("100% Crunch: Goblins") you can get 45 goblins (CRs 1/4- 5) by Raging Swan Press for $2.39. Some of those might be appropriate, though I doubt they come with songs or other details you're looking for.
- The Player Companion for Goblins of Golarion might be useful if you want to create your own, or modify goblins made by others.
- Lastly the Bloodmoon Goblins by Fear the Boot (mentioned by javafueled) is a supplement/campaign setting available for $4.99 and contains a full "Cast of Characters":
"A detailed dramatis personae with artwork, descriptions, and stat blocks for the tribe's most influential goblins. Each of the goblins' personalities and schemes are laid out in detail, allowing your PCs to enter a boiling cauldron of friends, enemies, and intrigues from the very first session of play."
The other content that comes with it might provide great resources and inspiration for play, especially if you plan on going beyond the We Be Goblins episodes. Note I haven't seen the content so I can't judge if these will work out of the box or if you'll have to modify.