For me in Colorado, I would say it is the Anaheim Outlaws. Since I joined Colorado, Anaheim has always been the team that no one likes. Being in the same conference as Anaheim in S54 then moving into the same division as them in S55 and on. So definitely our division rivals. We have played Anaheim 26 times since S54. Colorado has won 12 times to Anaheim's 14 wins. We have scored 90 goals against them and they have scored 83 goals. So advantage Colorado there. We have shut them out 3 times to only being shutout once. Also probably the best game I have ever been a part of in the SMJHL was against Anaheim. Colorado won 10-1. 
For reference, here is the game https://youtu.be/0XHBvojp5F0?t=571 
just absolutely crushed them. A very fun game to play in. The only thing is that the only playoffs matchups between us two teams (since S54) ended with Anaheim winning the series in 5 games. So hopefully we will get our shot to avenge this loss soon.
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