I've created about 20 reports under Event Reports but Civi seems to sort the report titles in order of creation. Is there way to have the report titles sorted alphabetically?
I don't think there is.
I would get around this by creating a new top level menu item called "XYZ reports" (assuming you work for company XYZ).
Then you can add major categories so that you can group reports as you want. (I have finance, membership, fundraising,training and marketing as my categories/parents for the reports.) Once you have assigned a report to the appropriate parent menu you have complete control over the order of the reports via Administer > Customize Data and Screens > Navigaiton Menu.