Name: Beatrix "Trixie" Pickles
Nickname: Trixie, The Mrs. (by Lou sometimes), Grandma (by the kids)
Age: Presumably 73 (deceased)
Spouse(s): Louis Kalhern Pickles II (widower, alive)
Other relatives: Charlotte and Didi Pickles (daughters-in-law)
Angelica Pickles (granddaughter), Tommy and Dil Pickles (grandsons), Miriam (cousin-in-law), and several other cousins from Lou's side of the family.
Beatrix, often called "Trixie," was the first wife of Lou Pickles. She has made no real appearance on the show but many of the characters have mentioned her several times, mostly through Grandpa Lou, Stu, and Drew. She's given a sort of speaking role in the episode Sour Pickles, when Lou reminisces on how he was left to take care of their toddler sons, Stu and Drew. She's heard in the flashback, briefly talking to Lou while he's trying to fix a toaster. However, her voice is muffled by the phone.
In Be My Valentine, she's given her first real appearance in a photo with her and Lou on a cruise ship. In that episode, Lou explains to his granddaughter, Angelica (who was dressed as Cupid), that he "got hit with Cupid's arrow" the day he met Trixie. Lou explains to his grandkids (and Chuckie and the DeVille twins) that he and Trixie met on a cruise ship, and while he was immediately in love with Trixie when they first met, Trixie wasn't in love with Lou at first. Lou was relentless in courting Trixie, he charmed her by taking her out to dinner, dancing, and enjoying the cruise night rides. Trixie slowly fell in love with the sweet, romantic and dashing but clumsy Lou Pickles. They were later married and she became the mother to Drew and Stu Pickles. It's shown that while Lou's known for his wild stories, Trixie was known for telling the truth of his stories. In A Rugrats Vacation when Lou begins to brag that he was a success in the casinos of Vegas and that they had to send him back to get rid of him. Drew adds, "Hmm, Mom (Trixie) said you lost everything but your underwear and had to be sent home on a bus". In the All Grown Up! TV Movie, Lou says that he met Trixie on a ranch.
Its never been said how Trixie Pickles died, but Lou often mentions how he keeps her dear in his heart (it can be assumed that she probably died sometime before Angelica was born). She's mentioned briefly in The Rugrats Movie, when Didi and Stu both believed (mostly because of Lipschitz's books) that their younger son, Dil, was going to be a girl at first, and they had planned on naming him Trixie, after Stu's late mother. But when they saw that he was a boy, they named him after Didi's cousin. She's also mentioned again in the beginning of Rugrats in Paris: The Movie, at Lou's wedding reception after getting married to his second wife, Lulu. Stu and Drew tell their dad that they're really happy for him and that they think Lulu's great. Lou agrees with his sons, but he admits that while does love Lulu, he'll always love their mom, and it was actually Lou's love for Trixie that helped him to love again.
Trixie was probably born in 1917 and died In 1990.
You can find Trixie Pickles gallery here.