Use WinRAR (the original developer), 7-Zip (a popular free, open-source alternative), or The Unarchiver for Mac.
Common for "Inspiration" or "Reference" packs used by artists and tattoo enthusiasts. Tattoo_and_Girls.rar
Because .rar files are frequently used to distribute large amounts of data, they can sometimes be used to bundle malware alongside legitimate files. Use WinRAR (the original developer), 7-Zip (a popular