Italian commercials and trailer often have different voices for some characters: as an example, Claudio Moneta did Terrafin and Trigger Happy in commercials for the first game and Pop Fizz in the Giants trailer, but never voiced anyone in the games until Trap Team, where he voiced Brawl & Chain and Wolfgang. At the same time, Marco Balzarotti (Pop Fizz's actual voice) did Tree Rex and Wash Buckler in commercials, but the latter is voiced ingame by Pietro Ubaldi, who also took the role of Eruptor in commercials but not in games, and both him and Dario Oppido voiced Snap Shot respectively in the trailer and commercials for Trap Team... role Marco Balzarotti took in the actual game.
Vaporware: Half of Battlegrounds. It has a level select for four worlds - but only two can be played, and as of nearly a year after its release an update to add the other two had not yet materialized. It's been updated and has been completed now, though.
What Could Have Been: There was a MMORPG being made named "Spyro's Kingdom". It was scrapped early on (though a pitch demo is available) due to the decision that Skylanders would be more profitable and bring in new fans.
Krypt King was originally conceived as the first Giant design, and was supposed to be a humongous version of Chop Chop, complete with shield. His name was even, during concepting, "Chop Chop Daddy". While he was eventually replaced with Eye Brawl, everyone at Toys For Bob liked him so much he was brought back, with a few aesthetic tweaks, as a Trap Master. Behold, his original◊ concept art◊.
Similar to Krypt King, Chopper was first created as a concept for a Giant, and would've been a huge T-Rex with guns and armor strapped to him (very much in the vein◊ of Wexter from Axe Cop). Unfortunately, they ran into problems both packaging him and fitting him on a portal with another Skylander, since T-Rex's are horizontal rather than vertical creatures, and he got replaced with Bouncer. Once again, I-Wei loved the idea so much that he revived it for Trap Team.
Do you remember that wizard from the Kingdom of Ice Adventure Pack in Spyro's Adventure and Giants? Believe it or not, he's actually the original concept for Double Trouble.
Arbo, the absent minded ent, was originally a full-fledged Skylander. He got as far as the toy stage◊ before being relegated to his current supporting role.