In Chrono Trigger for Nintendo DS and Wii, there are thirteen endings in all that you can see for various different story versions.
Here is the list of possible endings, and what you would need to do to see them.
Ending 1 “Beyond Time” – Defeat Lavos after reviving Crono at Death Peak
Ending 2 “Reunion” – Defeat Lavos while Crono is dead
Ending 3 “The Dream Project” – Defeat Lavos in the Ocean Palace or immediately upon starting a new game+
Ending 4 “The Successor of Guardia” – Defeat Lavos after saving Leene and Marle, but before visiting the End of Time
Ending 5 “Good Night” – Defeat Lavos after visiting the End of Time, but before returning to the Middle Ages
Ending 6 “The Legendary Hero” – Defeat Lavos after arriving in the middle ages, but before obtaining the Hero’s Badge
Ending 7 “The Unknown Past” – Defeat Lavos after obtaining the Hero’s Badge, but before the Gate Key is stolen
Ending 8 “People of the Times” – Defeat Lavos after regaining the gate key, but before giving the Masamune to Frog
Ending 9 “The Oath” – Defeat Lavos after giving the Masamune to Frog but before fighting Magus
Ending 10 “Dino Age” – Defeat Lavos after facing Magus, but before facing Azala
Ending 11 “What The Prophet Seeks” – Defeat Lavos after facing Azala, but before Schala opens the sealed door
Ending 12 “Memory Lane” – Defeat Lavos after Schala opens the sealed door, but before restoring the light to the pendant
Ending 13 “Dream’s Epilogue” – Defeat the Dream Devourer beyond Time’s Eclipse
