I had a look through all available rovers and rangers to determine their 2TR discount status;
Further to your post, ATOC have issued a further brief on which Rovers/Rangers have 2 Together discount.
Rovers/Rangers which have 2 Together discount are;
All Line Rover 7 Days
All Line Rover 14 Days
Anglia Plus 3-in-7 Flexi Rover
Anglia Plus Day Ranger
Atlantic Coast Line Ranger
Cambrian Coaster Day Ranger
Central Scotland Rover
Cherwell Valley Ranger Didcot
Cherwell Valley Ranger Oxford
Cherwell Valley Ranger Reading
Cheshire Day Ranger
Coast and Peak 4 in 8 Day Rover
Cumbria Day Ranger
Cumbria Round Robin
Cumbrian Coast Day Ranger
Dales Rambler Day Ranger
Devon Day / Evening Ranger
East Midlands Day Ranger
East Midlands Day Rover
East Midlands Rover
East Yorkshire Round Robin
Explore North & Mid Wales Flexi Rover
Explore South Wales Flexi Rover
Explore Wales Flexipass
Freedom of Devon & Cornwall 3 in 7
Freedom of Devon & Cornwall 8 in 15
Freedom of North East 4 in 8
Freedom of North East 7 day
Freedom of North West 4 in 8
Freedom of North West 7 day
Freedom of Scotland Travelpass 4 in 8
Freedom of Scotland Travelpass 8 in 15
Freedom of Severn & Solent 3 in 7
Freedom of Severn & Solent 8 in 15
Freedom of South West 3 in 7
Freedom of South West 8 in 15
Hadrians Wall Day Ranger
Heart of England 3 in 7
Heart of England 7 Day
Heart of Wales Circular Day Ranger
Heart of Wessex Day Ranger
Highland Rover 4 in 8
Kennet Day Ranger
Lakes Day Ranger
Lancashire Day Ranger
Lincolnshire Day Ranger
Looe Valley Explorer
Maritime Line Ranger
North Country 4 in 8 Rover
North Downs Day Ranger
North East Round Robin
North Wales Rover
North West Round Robin
Oxford Evening Out
Oxfordshire Day Ranger
Ride Cornwall
Shakespeare Explorer 1 Day
Shakespeare Explorer 4 Days
South Pennines Day Ranger
St Ives Bay Line Ranger
Tamar Valley Line Ranger
Tarka Line Ranger
Thames Branches Day Ranger
Thames Rover 3 day
Thames Rover 7 day
Tyne & Tees Day Ranger
West Midlands Day Ranger
West Wales Day Ranger
Yorkshire Coast Day Ranger
And Sleeper Tickets where the passenger boards the train before 0430.