You can go to Amazon, type Sherlock Holmes, and an almost uncountable number of stories by authors not named Arthur Conan Doyle will come up.
Some are very good, some are very bad, and others fall in between. I happen to think that August Derleth’s Solar Pons is the best Holmes pastiche you will find. For the most part, it’s not even debatable.
This post I wrote for my The Public Life of Sherlock Holmes column over at the Black Gate website is a pretty good overview of Pons. And if you want to delve a bit more deeply into “the Sherlock Holmes of Praed Street,” SolarPons.com is the only website dedicated to him.
Another Black Gate post I wrote looked at the four science fiction Pons tales that Derleth wrote with Mack Reynolds and I think it’s worth a read. We’ve even got a growing Facebook community, with over 130 members (I was just hoping to reach 20 when I started it).
The Pons tales are not out in ebook form, and the last major reissue of Derleth’s stories was by Pinnacle circa 1974. So, you need to look a little (but not too much) for used copies of a few of the collections. But if you’re a Sherlock Holmes fan, there’s a treasure trove of stories out there for you to discover. Come, Parker, the game’s afoot!