The TVTropes Trope Finder is where you can come to ask questions like "Do we have this one?" and "What's the trope about...?" Trying to rediscover a long lost show or other medium but need a little help? Head to Media Finder and try your luck there. Want to propose a new trope? You should be over at You Know, That Thing Where.
If the Ur-Example is distinct from the Trope Maker, then I guess the Ur-Example would qualify as "only an example of the trope in hindsight".
Unbuilt Trope may be of interest as well.
Trope Codifier for a work that helps define a trope without either creating it or necessarily popularizing it- Genre Popularizer is a separate trope.
Magical Girl Warrior makes a good example, because you can clearly trace it's development through the stages:
- Princess Knight - Trope Maker for "spirited girl and her tiny magical sidekick fight evil", but also an Unbuilt Trope example missing a lot of the conventions to come (for instance, she doesn't have overt magical powers)
- Cutey Honey - Trope Codifier, established a lot of conventions like a Transformation Sequence, flashy powers, a dash of romance, and a close-to-modern-day setting. Still Unbuilt in a lot of ways, though- for instance, as the amount of blatant Fanservice in the original cut would suggest, attracting a significant young female fandom was unexpected, and she's more of an old-school Henshin Hero that happens to be female than a magical girl.
- Sailor Moon - Genre Popularizer and Trope Codifier; broke into mainstream and global awareness, and established some of the final cornerstones of the genre like elements borrowed from the Sentai genre and The Power of Friendship as a core theme.
Which trope applies to a work using a trope before it became a trope? Ur-Example?