Unzip Online is described as 'free online tool that allows you to unzip files and optionally convert them to widely supported ZIP format' and is an website in the File Management category. There are more than 10 alternatives to Unzip Online, not only websites but also apps for a variety of platforms, including Windows, Linux, Mac and Android. The best alternative is 7-Zip, which is both free and Open Source. Other great sites and apps similar to Unzip Online are 7-Zip ZS (Free, Open Source), Explzh for Windows (Free Personal), ezyZip (Free) and TC4Shell (Paid).
Explzh for Windows is a file operation tool created with the concept of treating archive files, CD-ROM virtual disk images (ISO-9660 / ISO-13346), and FTP hosts as virtual folders and handling them like an explorer.
ZIP Extractor is a free, open-source application for decompressing ZIP files into Google Drive. Decompress ZIP files to Google Drive ZIP Extractor allows you to unzip (extract or decompress) files in Google Drive.