Is downloading games, programs, and copying operating systems from the internet for free – without purchasing them from their owners – considered theft that necessitates returning the rights to their owners, knowing that they were not used for sale?

Electronic games, if free from religious prohibitions and do not distract from obligations, are permissible. Downloading games for free from the internet is permissible if it is with the permission of their owners. However, for games whose owners reserve their copyrights and prohibit downloading them except for a price, it is not permissible to download them for free. If the games you downloaded for free are of the type that their owners do not permit downloading except for a fee, then this is an infringement on the property of others, and it is akin to theft and impermissible. Your duty is to repent to Allah by returning these rights to their owners or seeking their forgiveness, and you should exert your utmost effort in doing so. If you are unable to fulfill all of them, then fulfill what you can and resolve to fulfill the rest when you are able, and by doing so, your repentance will be complete. And whoever takes people's money with the intention of repaying it, Allah will repay on his behalf.