PortableSigner - PortableSigner is a signing (with X.509 certificates) program for PDF files.
Aspose.PDF for Java - Aspose.Pdf is a Java PDF component to create PDF documents without using https://alternativeto.
PDF24 PDF Creator - Create PDF and convert documents to PDF for free with the free PDF24 PDF Creator.
Tcpdf - TCPDF: Open Source PHP Class for generating PDF documents
AnyMP4 PDF Converter - With versatile and powerful functions, AnyMP4 PDF Converter can absolutely convert PDF format to diversified images (TIFF, JPEG, PNG, GIF, and others) and document files (Text, Word, Excel, EPUB, HTML, and more) on Mac.
IronPDF - SDK for creating and editing PDFs.