noise.sh - Excel for music producers and sound designers
Anvil PDF Filling API - The easiest way to programmatically populate any PDF
Composer's Sketchpad - A doodle-y iPad sequencer for making quick musical sketches
PDFShift - Convert any HTML documents to high-fidelity PDF using a single POST request
Helio - Design successful products by revealing key user behaviors
KDAN Mobile PDF Reader - PDF Reader is the one app you can rely on when you need a portable solution to work with PDFs.