Adiós: This is another common way to say goodbye in Spanish. It is a contraction of the words "a Dios", which means "to God".
Hasta luego: This phrase is used to say goodbye when you expect to see the person again soon. It literally means "until later".
Nos vemos: This phrase is also used to say goodbye when you expect to see the person again soon. It literally means "we see each other".
Hasta pronto: This phrase is similar to "hasta luego" and "nos vemos", but it is used to say goodbye when you are not sure when you will see the person again. It literally means "until soon".