I used to not be bothered by the fact that most of our liturgy and other Torah-related writings have much of any reference to the maid-servant foremothers, but a particularly feisty tour guide in the Old City of Yerushalayim started railing about it one day.
She wondered why no one seems to care where Bilhah and Zilpah are buried. We know where Rachel and Leah are - in a roadside grave/memorial and Ma'aras Hamachpelah respectively. What about the other half of Yaakov's wives, who produced 1/3rd of the shevatim, Klal Yisrael's ancestors?
One could venture to say that nowadays, since the exile of the 10 "Lost Tribes," Bnei Yisrael consists of members from the tribes of Levi and Yehuda who were born to Leah along with Binyamin who was born to Rachel. As such, we don't really have any connection to Yaakov's 3rd and 4th wives.
However, we also know that, to a degree, many of the members of the "Lost Tribes" may have been found and returned through the various groups from far away locations that have proudly identified themselves and begun the process of moving to the State of Israel. Of note is Israel's Chief Sephardic Rabbi Shlomo Amar recognizing the Bnei Menashe of India as one of the 10 lost tribes back in 2005.
On a less recent note, I recall hearing/learning that a number of our exiled brethren did indeed join up with the remaining community either in Israel or in Babylonia before the time of the 2nd Commonwealth and the rebuilding of the Beis Hamikdash. I think the same source remarked that not every last member of these 10 tribes actually left when the vast majority of the Northern Tribes were exiled, which means we never totally misplaced them in the first place.
I'm not going to discuss the Talmudic references here, since that's not really the point of this post.
Back to our near-forgotten foremothers.
Thinking to myself, I didn't think I had ever met anyone named after Bilhah and Zilpah, nor had I seen a memorial/dedication plaque of any sort that listed such a name. Then one day, ASoG mentioned the name of a family friend's mother who was ill and needed tefillos said on her behalf, and lo and behold her mother's first name was Bilhah! Sufficed to say, I was a bit flabbergasted, but in a good way.
Before completing this post, I decided to Google "Bilhah" and "Zilpah" to see what I could find.
First, it seems I was mechaven to a 2004 post by A Simple Jew who also wondered "Whatever happened to Bilhah and Zilpah?"
I also found an "Ask the Rabbi" question on Chabad.org which discusses why we don't mention Bilhah and Zilpah as matriarchs like Rochel and Leah.
Lastly, a comment on A Simple Jew's blog led me to check Wikipedia, which informed me that Bilhah and Zilpah are buried at the "Tomb of the Matriarchs" in Tiberias, which would seem to indicate that we indeed treat them as full-fledged Imahos. I had not heard about this particular grave site before, and find the list of women who are buried there to be a fascinating collection of important Biblical figures.
Do you know anyone named Bilhah or Zilpah?