Lumin PDF for G Suite - Open, edit and share PDF and Office files in your browser.
PdfPig - Read and extract text and other content from PDFs in C# (port of PDFBox)
DocuSign - Try DocuSign's interactive signing demo now! Send yourself an electronic document to digitally sign using our e-signature service.
Document .Net - Gives you API to do everything with a document in PDF, DOCX, DOC, RTF, HTML and Text formats.
GTasks for G Suite - Lets you to manage your Google Tasks from Docs allowing you to tackle your to-do list.
PDFSharp - Office & Productivity and Development