I've noticed the message on the game's Facebook page, so here's the list of transformers mentioned in the game files (to be accurate, in the file "LangConfig.bytes" along with lots of interesting data, like mission stories and other things). I decided not to post this information on the official page, because the developers would probably just encrypt this file to prevent its usage.
Note: the file also contains some characters, which are not currently in game, but will be added later. I don't know this Wiki's policy for such characters, so I'm going to include them with others. The listing order is the same as in the file itself.
Autobots:
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Decepticons:
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