- Hellboy (2004) His breakout role was as the aquatic Abe Sapien, who was otherwise voiced by David Hyde Pierce.
- Pan's Labyrinth (2006) He worked with Guillermo del Toro as the standout Pale Man.
- Fantastic Four: Rise of the Silver Surfer (2007) He performed the role of the Silver Surfer, which was otherwise voiced by Laurence Fishburne.
- Hellboy II: The Golden Army (2008) Reprised his performance as Abe, plus appeared as a few other characters.
- John Dies at the End (2012) Oh, um, spoiler alert...
- The Neighbors (2012-2013) Sitcom about aliens.
- Falling Skies (2013-2015) TV show about an alien invasion.
- The Strain (2014-2016) TV show based on a concept by del Toro.
- Rent (2005) With Rapp I'm going to summarize his career with his lead role in this breakthrough musical about the emerging new mainstream, which he originated in the Broadway debut and reprised in the later movie adaptation (starring opposite Rosario Dawson in that version; how awesome would it be to see her stop by Star Trek?). He'll be making franchise history as the first openly gay character conceived as gay (remember the retrofitting of Sulu in this past summer's Star Trek Beyond), and he's got the history to prove he'll be taken seriously for it.