Windows

 ·  VeraCrypt
 ·  BitLocker

I recommend VeraCrypt instead of BitLocker. There is no proof that BitLocker is backdoored, and it probably isn’t, but as it’s closed source we can’t know for sure what the code is really doing. Also, the default settings on BitLocker backup a copy of your decryption key to your Microsoft account. There is an option to disable this during the setup, but I think something like this should really be opt in rather than opt out. While some people might actually prefer to backup a copy of their key, it gives Microsoft the ability to see that key too if they wanted. Nobody should have the ability to know your key or decrypt your drive except you, unless you expressly take steps to enable them.

Linux

 ·  LUKS

Most distros will have an option to enable LUKS encryption during installation.

Mobiles/Tablets

To Be Added