Formal:
* Magnifique: This is the most common and formal way to say "wonderful".
* Splendide: This means "splendid" and is a slightly more elevated way to say "wonderful".
Informal:
* Génial: This is a more casual way to say "wonderful", similar to "awesome" in English.
* Super: This is a very informal way to say "wonderful", similar to "great" in English.
* Formidable: This means "formidable" and is a more informal way to say "wonderful" that carries a sense of admiration or awe.
You can also say "c'est formidable" or "c'est génial" (it's formidable/it's awesome) to express your enthusiasm about something.
Remember that the best translation will depend on the specific situation and the relationship you have with the person you are speaking to.