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
Custom Handmade Redirect Lightning proxies made from real Magic the Gathering card with many different alternated arts available for purchase.
Even though the main set was released in June, Wizards of the Coast had planned a holiday release for November 3 It wasnt initially clear exactly what the holiday release would entail until todays preview panel at MagicCon Las Vegas, where we learned that it will feature new scene boxes and new card styles in special edition Collector Boosters
With this creature on the battlefield, the controllers no longer have to worry about important Eldrazis heading to the graveyard
For starters, the front side of Kefka is a totally fine Commander by itself
The ability says you may create tokens, making it entirely optional