Few content types in a View
It sounds like you're looking for a Contextual filter. 

You create a Page Display with a path of your choosing that is displaying many Content types. This is your page that lists all of them, for example my-content-types. 

Then you add a Contextual filter to that View called Content type from Content Category. 

Configure it with these options:
    When the filter value is NOT in the URL
    Display all results for the specified field
    When the filter value IS in the URL or a default is provided
    Specify validation criteria
    Validator Content type
    Case in path Lower case
    More
    Transform spaces to dashes in URL

You can leave other options as default, although you should read them all and adjust to your needs, for example what Views should do in case your argument doesn't validate, or you need more than one content type filter on the same page. 

This Contextual filter adds options to your path based on the content types you have on your system. If you add the name of a content type to your path (in your browser Location bar): 
my-content-types/article the Views results will reduce the list to only show Article nodes. 

If you enter a path my-content-types/page it will list only Basic page nodes. 

There is also an option to override the Title if you need to correct it to name only the content types filtered out. 

If you set your Contextual filter to allow multiple values (there are two places for that) you can construct the path with two or more content types to filter them out: my-content-types/page+article. 

To test that your Contextual filter is working you can enter the argument for it in the Preview with contextual filters: field and hit the Update preview button if you don't have it set automatically. To view all the results without filtering simply delete the argument or enter all at the Preview or at the end of your path.