@Emmacox I was curious and took a look at the options available with Scrivener. Apparently, they don't provide any way to script or to add plugins. So apparently that path is out 😞
However, they do have an option under Edit > Writing Tools > Linugistic Focus... which allows you to find some types of words. But not words from a custom list.
The Scriverner documents are just RTF files. So it should be possible to simply load the files in a separate app and do any kind of search you want. I might look into this if I have some time.