Items are added to the database as-needed by users.
We have a group of volunteers ("Name Tribunal") that will try to approve official names for consistency. But, they only work with existing listings. So, users have to create them first. Someone has to be the first. It's also means our database is sometimes sparsely populated (especially for games that may be somewhat obscure or new).
For New Layout, do a search, then use the "Add Unlisted Game
" button on the left. It brings up a form where you can enter anything you want. Old Layout users can use the add links on the My Items page.
In the case where the item is listed for one platform but not the one you want, a trick that makes this easier is to add it initially using the other platform, then edit your listing to change just the platform to what you want.