arjaybe, a trope is a recognizable literary device based on content. (I.e. alliteration is not a "trope.")
If it's done too often, especially poorly, it becomes a cliché. So: A trope is a cliché that's not yet boring. If a trope is popular enough, it can be an entire subgenre.
tvtropes covers quite a lot of them (it misses a number of common fanfic tropes, for obvious reasons - fanlore.org
tries to cover those), but since their initial focus was on TV, the descriptions aren't always useful for literary purposes. They also don't separate out common tropes, or tropes-by-genre, in a way that's useful for discussing literature, and their trope names are pop-culture based instead of academic.
In addition to wikipedia's (often excellent) lists of literary techniques, including tropes, gaming sites may have lists of
character tropes and
plot devices, although these specific ones are use pop-culture phrasing.