WiseStamp - WiseStamp allows you to easily create and implement slick and unique email signatures for your business.
Apache PDFBox - The Apache PDFBox™ library is an open source Java tool for working with PDF documents.
MySignature - MySignature is FREE Email Signature Generator that helps to create Professional Signatures for major email clients such as Outlook, Gmail...
iTextPDF - iText offers flexible tools for PDF creation, editing and inspection.
Sigstr - Email signature marketing
Qoppa jPDFFields - Use jPDFFields Java PDF SDK to work with interactive PDF forms in both AcroForm and XFA formats.