To start, it's great that you've acknowledged that a lot of ideas aren't really new under the sun. That'll break down some of that stress of creating new ideas. In this case, I'd say that "original" for you would be "new ideas I've yet to explore". That could be a type of genre, types of characters, settings, or even relationship tropes.
For myself, when I want to think of new ideas, I think about the themes I want to explore. Doesn't matter whether or not those themes have been used in other tropes. The important theme here is to think of the theme. Because from there, I am able to translate that theme MY way.
A theme I love to use? Death & The Maiden. It's a common motif in many genres, especially horror romance, and it stems into many tropes: star-crossed lovers, beauty and the beast, immortality, tragic romance. Hell, even the mythology of Hades and Persephone is based in that motif. It's one of the oldest ones around, but it still becomes fresh each time.
Even more, themes shift tones depending on the genres you're working with. Sometimes, Death & The Maiden is tragic (especially if it's in romance). Sometimes, it's terrifying (horror), and other times, it's curious (fantasy, fables). You could even take it a step further and put it in modern settings (Noir, Crime, Slice of Life).
So when we already know things might not be new, we take their themes and see "how do they interact in other settings? How do they interact with other genres?" There is no one way to show a theme, and there is no one way to show a trope.
And just in general -- branch out a bit. You seem to do a lot with fantasy. How about seeing your character from a different lens, like comedy or crime or drama? The moment the tone shifts, the ideas and themes shift as well. Or maybe they don't, and they become stronger.