Here are some other options, depending on the context:
* Tot later: This means "until later" and implies a slightly longer time than "Tot gauw".
* Tot binnenkort: This literally translates to "until soon", and it's a good alternative to "Tot gauw".
* Tot de volgende keer: This means "until next time" and is suitable for more formal occasions.
It's worth noting that "Tot ziens" is also used in Dutch, but it's more formal and less common than "Tot gauw".