A few options for reward seats. If you are SG or WP status and looking for economy class award availability on-line at QF's FF pages, you will automatically see the combined availability of X and T buckets.

You can also use one of the various on-line availability tools such as the Carlson Wagonlit ITN system or Cathay Pacific ITN system. I also use the KVS Availability Tool. However, these don't always show all fare buckets and the buckets they do show vary from day to day. For example, none are currently showing X or T, while only the CX tool is showing U (business class awards).

But I am assuming the OP was using the QF web site to view available award flights. And since you use your FF number to sign into the system, it know whether to show the extra T bucket availability for SG/WP status or to just show the X availability for everyone else.