If you are looking for the classic Jeremy Brett series, an episode index and historical data are hosted on the Arthur Conan Doyle Encyclopedia For archival purposes, Archive.org
: Holmes and Watson meet and investigate a series of mysterious "suicides" [8, 16]. The Blind Banker
: Offers the modern BBC series starring Benedict Cumberbatch.
Typically, such “index of” pages are directory listings (often unlisted or unofficial) that contain downloadable episodes. A few things to consider before trusting or using such a link:
: Holmes and Watson meet and investigate a string of apparent suicides. The Blind Banker