Being a horror lover, I am always excited when I find a horror novel with my name in the title. It has happened more often that I thought it could. There are plenty of scream queens named Katie too!
Books:

Katie by Michael McDowell – “Katie never killed with kindness”
This was the book that started off my collection of horror Katies. The story has a lot in common with the real life Bloody Benders, which was a family of serial killers who preyed upon guests at their inn. Kate Bender was likely the inspiration for Katie Slape, whose preferred murder weapon was a hammer.

Katie’s Terror by David E. Fisher has a couple of creepy coincidences about it: the titular Katie is a librarian, and her last name is Townsend (my hometown!).

Kate’s House by Harriet Waugh is one I haven’t read yet, but I do own a copy! I love that this Kate is a child who murders people via dollhouse.
Movies:

In Paranormal Activity (2007), a woman named Katie (also played by an actress named Katie) is plagued by strange events in her home.

Abandon (2002) is another movie where the character named Katie is also played by an actress named Katie (in this case, Katie Holmes). It’s more of a psychological thriller than horror, but Katie does murder someone, so it’s going on this list!

Kill Katie Malone (2010) “Never buy a demon on the internet”
This one isn’t even available on Netflix, so I’m not sure where I’m going to find it in order to watch it! Apparently Katie Malone is the ghost of an Irish servant who decides to have her revenge on the idiots who buy her off eBay. Sounds like something I’d do.
Apparently Kate & Katie are both pretty common names in movies – click on the link to find out how common your name is!