What I have wanted to do for some time, well over a decade, is to create a search engine that just searches page titles. Not as a substitute for any other search engine but as a high throughput discovery tool to screen for websites which can then be explored and searched further.
There are, e.g., search engines that search for strings in the page source, e.g., to detect use of certain Javascript files. These are slow and not free.
There are, e.g., search engines that search for strings in the page source, e.g., to detect use of certain Javascript files. These are slow and not free.