There are numerous types of challenges and rewards on Wikipedia: the featured articles, the writing and translation challenges, the Wikicontest, etc.
The best articles, the ones that follow the Wikipedia criteria of being encyclopaedic, neutral and exhaustive, are hailed after a vote as being “good” articles, or for the most complete, “featured” articles. These labels reward the efforts put in by all the writers of the article.
On Wikimedia Commons there are three types of label based on the quality of the photos: featured images, quality images and valued images. These labels are awarded by a vote based on precise criteria and anyone can propose their own photos.
Photo: The central part of the ceiling of the Battles Gallery in the palace of Versailles by -donald- (CC-By-SA 3.0) - Placed first in France in the competition of Wiki Loves Monuments