@spectralcatnap
You should totally give Calamity Fables a try! It's made by a different group who also used to work on the original Calamity mod.
I personally loved the boss battles it has to offer. It has newer animations, new sounds and even dialogue! (I couldn't believe it either.)

My personal favorite boss fight from it was Crabulon. The new animations and simple mechanics they added for it made the fight so much more refreshing and exciting. And, when you fail to it, if you do that is, it does the Crab Dance on your face and goes back down. How cool is that?

Unfortunately, it is only for pre-hardmode, as far as I know of. But, that doesn't mean it cannot be enjoyed till you reach Hardmode!
I heard it was compatible with the OG Calamity mod but, I'd suggest you play it alone with a few QOL mods to accompany it!