Is there way to find where I've used a font style?

Hi, Alejandro.

Not sure if this will solve your problem but you can try selecting a text layer with specific font style and use this:

It is a work around I guess, but I have to go inside every single page and check. Is there a way to do it with through the whole document? Perhaps a plugin? Thank you btw! it still helps.

For plugins, not entirely sure. I’m not familiar with plugins 😅

In other way around, you could use the plugin called Design Lint

It shows what font styles are used for the selected frames. So much useful to identify the text without styles.

I used Style Organizer before and I can recommend it
https://www.figma.com/community/plugin/816627069580757929/style-organizer

However it works per page, not per file.
But maybe you could move all you stuff to a single page, run the plugin, do the cleaning, and move everything back.