Endings Acquired: The rest of em
The final endings are, I believe, various offshoots of the canon Millennial Fair ending, though they can be quite a bit different depending on when Lavos was defeated. If you did the deed before resurrecting Crono, then the party doesn't learn about the Chrono Trigger until later, thus ending the story with everyone making a determined effort to bring back C-dog. Whether or not Magus is a part of this ending (and whether or not Frog becomes human) depends on how the party dealt with Magus in the game.
You can change the ending further by crashing the Epoch into Lavos, but I have yet to find these endings online, nor do I know how to even accomplish this in the game. Smaller changes abound as well, such as the status of Lucca's mom. From what I've seen, my favorite change is definitely the humanized Frog and Lucca's reaction to him. Such a dish!
And well... that caps off two complete playthroughs, all the side quests, and a full-n maxed out level up grind. I'd say that does it for new discoveries! All that's left for me is to rank some stuff and end with my final thoughts about the game.
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Yoblazer: http://i33.tinypic.com/ml36gl_th.gif
Watch and you'll see... someday I'll be... part of your world!