You can see every item currently wanted by users of Everygamegoing here, and you may filter by the machines those items are for. If a certain machine is missing from the dropdown, it means there are currently no items wanted by any users for that machine.
To contact other users in respect of items they want, you will need to be logged in.
If you have added your own collection to Everygamegoing (and you have logged in), you can scan it for any items wanted by others.
Alternatively, if you want to view all the wanted items of a specific user (whose e-mail address you know), click here.