Molly's cat (it's totally canon, based upon the Molly Hooper tie-in blog for S1) is named Toby. She considered naming him Sherlock, but then thought against it. While browsing Wikipedia on the name (for my own interests, not to mention I'm taking a break from a HUGE homework assignment), I find this little tidbit about fictional characters by that name.
Toby, partial bloodhound in the Sherlock Holmes tale, The Sign of Four.
:-O
Toby is a dog who is used by Sherlock Holmes. He is first introduced in The Sign of the Four and is described by Watson as a "ugly long haired, lop-eared creature, half spaniel and half lurcher, brown and white in colour, with a very clumsy waddling gait." Though used by Holmes, the dog belongs to Mr. Sherman who keeps a menagerie of creatures at No. 3 Pinchin Lane in Lambeth. Toby lives at No. 7 within his house. Holmes states he would "rather have Toby's help than that of the whole detective force in London." and requests the dog by name.
Toby also featured in the novel Sherlock Holmes VS Dracula, when Watson and Holmes called on Toby to track Count Dracula after finding him in a meat-packing district- Dracula's carriage having rolled through a distinctive piece of rubbish-, allowing the two to track Dracula to Watson's house in time to learn that he has abducted Mary Watson.
In the Holmes-esque The Great Mouse Detective, Toby is a Basset Hound and a permanent resident of 221b Baker Street. He is frequently used by Basil, the eponymous protagonist, as a means of transport and to pick up trails.