Formal:
* À bientôt: This is the most common and formal way to say "see you soon" or "talk to you soon."
* On se reparle bientôt: This literally translates to "we will speak again soon."
Informal:
* On se dit à plus tard: This means "we'll talk later," but it's more casual and suitable for friends or close acquaintances.
* À tout à l'heure: This translates to "see you later" and is used for situations where you'll see the person again soon.
More specific:
* On se parle demain: This means "we'll talk tomorrow."
* On se voit plus tard: This translates to "see you later" and implies that you will be meeting in person.
Ultimately, the best option depends on the situation and your relationship with the person you're speaking to.