To return unlimited results, just drop the
$limit=1000 from the query.
EDIT: Indeed SharePoint by default returns 100 items of the list. The correct way to return a bigger subset of items would be to use
$top= in the query. However, note that this default value of 100 is implemented most importantly for performance reasons. This means that it would be advised to implement paging for your returned items showing e.g. 100, 200 or 1000 items per page. This has been discussed e.g. here: List API get all items limited to 100 rows
To properly filter the return, the syntax needs to be
$filter=<column> <operator> '<value>'. Pay attention to the spaces! So in your cases the query would be:
/_api/web/lists/GetByTitle('ListName')/items?$top=1000&$filter=status eq 'ok'