Besides for sending to Rivkah, כלי כסף וכלי זהב ובגדים – “silver and gold jewelry and clothing”, which are the sivloinus in Maseches Kiddushin which are given to the kallah, we also find that he sent, ומגדנת נתן לאחיה ולאמה – “pleasant foods he gave to her brothers and her mother” (Bereishis 24:53). Rashi explains that he sent fruit of Eretz Yisrael which he brought with him. However, the Targum Yonasan ben Uziel interprets it as 'ודורונין' which means presents. These were like the sivloinus of Bava Basra, that are sent to the kallah’s house.
The Sivloinus that Hashem Gave to Klal Yisrael: The sefer HaMata’amim (המטעמים) writes that some have the minhag to send sivloinus from the chosson to the kallah in remembrance of the gifts that Hashem gave to Klal Yisrael before giving them the Torah. Before receiving the Torah, Klal Yisrael were given spoils from Mitzrayim, spoils from the sea, the mon, a special well and quail. Many customs that we do for a chosson and kallah are based on what happened at Mattan Torah, therefore, since before Matan Torah we received lots of gifts, we do the same thing by a chosson and kallah.
