Formal/Literary:
* Finis
* Thus concludes our tale.
* And so it ends.
* The curtain falls.
* The story is told.
Informal/Modern:
* That's all, folks!
* End of story.
* The End (for now).
* To be continued... (If there's more to come)
* Stay tuned... (If there's more to come)
Humorous:
* And that's how I met your mother.
* The adventure continues... in the next chapter.
* Spoiler alert: everyone dies.
Specific to a story type:
* Epilogue (For a novel or short story)
* Fade to black. (For a film or play)
* Curtain call. (For a play)
The best alternative for you will depend on the tone and style of your writing.