General Synonyms:
* Aha!
* I've got it!
* I see!
* There it is!
* That's it!
* Bingo!
* Gotcha!
* Found it!
* Success!
* Triumphant!
More Specific Synonyms:
* Epiphany
* Revelation
* Insight
* Discovery
* Breakthrough
The best synonym will depend on the specific context and the intended meaning.