Display a view block with a list of content excluding the one currently displayed on the page
Considering the first option, it is simple :

add a contextual filter of type "ID: Content" with the following configuration :


WHEN THE FILTER VALUE IS NOT AVAILABLE > provide a default value > content id from url
Go all the way down in the "more" section, expand it and check "exclude". 
Then click apply
And save the views


That's it !