UPX is a file compression and decompression software designed for Windows, MacOS, and Linux. It is one of the most popular file archiving utilities in the world. The software allows users to quickly and easily compress and decompress files in various formats, including ZIP, RAR, TAR, and 7z. The software is designed to reduce file size and save storage space, while maintaining the integrity of the file. UPX also offers advanced features, such as batch processing, image and video compression, and password protection. Additionally, the software provides support for a wide range of formats, including PNG, JPEG, TIFF, and many more. UPX is an ideal choice for those who need to quickly compress and decompress files.
The main purpose (and intent) of upx is to compress files. The main purpose (and intent) of themida is to obfuscate files and unnecessarily add some MB (bloatware).
ExEinfo PE
VMProtect
Free UPX
ASPack
Crinkler
PECompact
Themida
Exeinfo PE detects the type of packer/compiler, etc., used by an executable, but UPX actually "packages" the executable.