Travelcard - Hounslow loop and Kingston loop allows you to do the 455s, 450s and 458s. You don't have to limit yourself to Clapham Junction - Waterloo.
444s and 15X's can be covered by the excellent value Severn and Solent Rover.
456s are the tricky ones, but really one should have done a majority of them when they were with Southern and news came out that they were heading to SWT. They work some certain peak 10-cars so they can be done on a Travelcard. Once the 707s arrive, there should be more of the 10-cars on suburban routes so they will be easier to get on a Travelcard.