If you were wondering, and I’m sure you were, of 961 listed credits, by far the two most used pieces of Wagner’s work in television and film are the Bridal Chorus from Lohengrin (Here Comes the Bride, you philistines), and the Ride of the Valkyries from Die Walküre. Neither of these are particularly surprising. They are distantly followed by the prelude to Tristan und Isolde — which is a stunning piece of music — and the overture from Tannhäuser — which is lovely, but doesn’t do much for me. And then eventually you get a smattering of the overture from Lohengrin and Siegfried’s Funeral March from Götterdämmerung, which is, as previously noted, one of my favourite pieces of music ever ever. And then lagging behind you get your Flying Dutchman and your Mastersinger of Nuremburg and your Rienzi Overture (which I quite like even though it often strikes me as somewhat disjointed, especially for someone like Wagner) and more individualized pieces from the Ring Cycle and his other operas.
If you’d like to see the full list, you can find it here.