Were already seeing Zendikar Rising experiment with using different card types as the front side of these, which will affect deck-building and combo options across various formats (the front side determines how you can search for or target these cards when they arent in play)
In general, I would look at these two factors when looking to include cards not of your tribe's creature type: Is this creature so strong that it, on its own, is generally stronger than my tribal creatures when they are receiving bonuses and/or empowering my other cards
Ok Mega Absol Ex #161 (Pokemon Mega Evolution) Details All prices are the current market price
Can you believe that Winterspell is the 11th set to be released for Disney Lorcana
Spectacular ShowdownSpectacular Showdown (36,526 Inclusions, 1% of 2,721,129 Decks) You could not have designed a card more perfectly to fit Elsha, Threefold MasterElsha, Threefold Master than Spectacular ShowdownSpectacular Showdown
Before you know it, youll have a boatload of mana to work with