There isn't a list per se as the answer to the question depends on the permitted routes from the particular station to London.
In the case of Redhill, you have the following (assuming the ticket is routed any permitted):
You may travel to London on direct trains, but only as far as City Thameslink on Thameslink services. Routes that are served by direct trains are not neccesarily permitted routes if you don't use a direct train.
The shortest route or any route within three miles of it.
By my reckoning, the shortest route is direct to London Bridge at 20.75 miles. Also allowed are:
Victoria 21 miles
Blackfriars 22.5 miles
City Thameslink 23 miles
Waterloo East 21.75 miles
Charing Cross 22.5 miles
Cannon St 21.5 miles
Vauxhall (changing at Clapham Jn) 21 miles
Waterloo 22.25 miles
Also mapped routes defined in the Routeing Guide.
Routeing permissions for Redhill-London Group are:
LB, LB+SL, SC
http://www.atoc.org/clientfiles/File/permitted_route_identifier.pdf page 800
LB gives:
Redhill-Croydon-New Cross Gate-London Bridge
Redhill-Croydon-Crystal Palace-Tulse Hill-Peckham Rye-London Bridge
Redhill-Croydon-Crystal Palace-Tulse Hill-Herne Hill-Blackfriars
Redhill-Croydon-Crystal Palace-Tulse Hill-Streatham Group-Clapham Jn-Waterloo
Redhill-Croydon-Crystal Palace-Tulse Hill-Streatham Group-Clapham Jn-Victoria
Redhill-Croydon-Selhurst-Streatham Group-Tulse Hill-Peckham Rye-London Bridge
Redhill-Croydon-Selhurst-Streatham Group-Tulse Hill-Herne Hill-Blackfriars
Redhill-Croydon-Crystal Palace-Streatham Group-Clapham Jn-Waterloo
Redhill-Croydon-Crystal Palace-Streatham Group-Clapham Jn-Victoria
Redhill-Croydon-Selhurst-Streatham Group-Clapham Jn-Waterloo
Redhill-Croydon-Selhurst-Streatham Group-Clapham Jn-Victoria
Where a route into London Bridge is shown, you may continue to Blackfriars, City Thameslink, Cannon St, Waterloo East or Charing Cross.
Where a route into Blackfriars is shown, you may continue to London Bridge, City Thameslink, Cannon St, Waterloo East or Charing Cross.
Where a route into Waterloo is shown, you may continue to Blackfriars, City Thameslink, Cannon St, London Bridge or Charing Cross.
http://www.atoc.org/clientfiles/File/Maps.pdf page 57
LB+SL gives:
Redhill-Croydon-Selhurst-Streatham Group-Tulse Hill-Peckham Rye-Denmark Hill-Blackfriars
Redhill-Croydon-Crystal Palace-Streatham Group-Tulse Hill-Peckham Rye-Denmark Hill-Blackfriars
Redhill-Croydon-Crystal Palace-Tulse Hill-Peckham Rye-Denmark Hill-Blackfriars
http://www.atoc.org/clientfiles/File/Maps.pdf pages 57 and 99
SC gives loads, see
http://www.atoc.org/clientfiles/File/Maps.pdf page 95