check the RSS feature, this is the best way to have all items. but if you really want a link that lists all the items in the system,

then you have to request it as a custom programming, but the issue if your system database is too large this will be an overload

to your server specially if your site has a heavy traffic.

there is a feature in the listing options that allows you to list all items in the subcategories under their parent categories, check it

it may be what you want.

There is a trick that you can also try, the new autions link , you can set its date in the admin to very big value and it will list

all the items and you can change the text  for that link from New to All Items.

Thanks

Mewsoft Support
www.mewsoft.com