What are best free packers / obfuscators by your opinion ?

I see people recomend upx, but whats the use if you can just upx -d lol.exe

 

the use is to win size, upx is fine and open source.

It depends on what you want from a packer. UPX is probably the most used and one of the best compression executable "packers" but it sounds like you want a protector and not just a packer and as you have said UPX is no good as a protector which it never claims to be but is commonly used to reduce file sizes and a very basic obfuscation protection with no AV false positives

There are probably hundreds of topics on this forum which ask the same question about protectors but if you really cant find an answer  that suits you then at least provide detailed info of what you really want the packer / protector / obfuscator to do and what language your program was written in or you will keep getting unsuitable suggestions

Ok I've expressed my self badly, protection softwares like VMProtect ?

upx is nice packer