From Monotype Imaging:
SkyFonts (64-Bit) is an app for those that love to try out new typefaces. SkyFonts service expands creative freedom by providing on-demand access to thousands of fully-functioning fonts for use within all of your applications and devices. Give any font a try for free. If you like it, pay for it for only as long as you need it. Download and browse and rent SkyFonts directly from your iPad. With intuitive controls, you can easily browse fonts by name, foundry, as well as visual characteristics like weight, width, and x-height.