Lady Dedlock telling Esther she is her mother, but they can never meet again. The entire scene is heartbreaking.
Everything about Jo's death. Just as sad is Mr. Jarndyce's comments afterward (lifted almost directly from the book).
Jarndyce: Dead, your Majesty; dead, your Worships; dead, my lords and gentlemen; dead, right reverends of every order and degree. Dead and dying thus around us... every day.
Richard's death. His naivety and boyishness have him talking him of the future and asking to come home to Bleak House 'when he is back in his feet' even as he is dying of consumption.
Miss Flite's finally freeing her birds is both beautiful, heartbreaking and cathartic particularly when she comes to those she has named 'The Wards in Jarndyce' after Ada and Richard.
Whilst hunting for Lady Dedlock, Bucket suddenly realises the one place he hasn't tried; he and Esther run to Nemo/Hawden's grave, where Lady Dedlock lays dead in the rain, still looking out at her daughter.
Sir Leicester laying flowers on his wife's grave, remarking how he wished she had known that he still loved her.
