VueScan, Simple Scan, CopyFish, Epson Scan, XSane, WinScan2PDF, Genius Scan, gscan2pdf, Readiris, PDFTK Builder, fiScanner, ABBYY FineReader Online, ScanDrop, Windows Fax and Scan, SilverFast, Skanlite, OwlOCR, SwingSane, OpenScan, FreeKapture, PaperScan, Scanitto Pro, Easy Screen OCR, fileee, Opendias, Mopria Scan, CloudScan, Softi Scan to PDF, JetScanner, AXPDF Scan to PDF Converter, Flegita, MetaDMS Scan Software, DataCapture.io are some alternatives to NAPS2.