https://www.cbr.com/saddest-law-and-order-svu-deaths/

Law & Order: SVU fans have witnessed numerous heartbreaking deaths in the series' 25 seasons, but some are far more devastating than others.

I don't miss Sonya Paxton. I couldn't stand her.

Two heartbreaking deaths of one-episode characters in SVU's post-Stabler era:

Micha Green in "Funny Valentine"
Esther Labott in "The Book of Esther"