The only one I can think of is the outboundary Travelcard, but starting at the far end you'd need a Boundary Zone 6 extension to Epsom to use it as the zone boundary is at Ewell West and Ewell East.
Not sure of any combinations or how they relate to the Oyster cap ( with a railcard the Travelcard would be £10.55; not sure about the BZ6 - Epsom bit ) - I'm sure someone will be able to give that detail shortly.
Your Travelcard price is wrong. A zone 1-9 Travelcard is £10.10 with a Railcard, compared to the Oyster cap at £9.30 (the same price as the zone 1-6 cap), which won't be hit if I just do these 3 single journeys:
Brondesbury - Hackney Central off-peak: £1.05
Hackney Central - Clapham Junction - Epsom peak: £5.50
Epsom - Brondesbury off-peak: £2.50
Total: £9.05 (but at this price I would rather cut through central London and hit the cap for the Hackney - Epsom journey)
By introducing a paper ticket there may be following combinations:
Hackney Central - Epsom via Surrey Quay return: £1.05 + £6.85 (paper) + £1.05 = £8.95
Hackney Central - Epsom via Surrey Quay single: £1.05 + £5.90 (paper) + £2.50 = £9.45
Brondesbury - Epsom via Kensington Olympia return: £1.05 + £1.80 + £6.85 (paper) = £9.70
Clapham Junction - Epsom return: £1.05 + £1.80 + £5.45 (paper) + £1.05 = £9.35
Clapham Junction - Epsom single: £1.05 + £1.80 + £4.15 (paper) + £2.50 = £9.50
The "via Kensington Olympia" route is only available from the furthest east at Caledonian Road & Barnsbury, while the "via Surrey Quays" route is available starting from Dalston Junction and eastwards.
So is it possible to beat the £8.95 total above (apart from using a TfL bus to go to Epsom or avoiding the evening peak)? If I can bring down the total to below £8 I am willing to take a much longer journey compared to going via Zone 1, Otherwise I'd rather just use Oyster and travel whatever the fastest route is, i.e. cutting through Central London between Hackney and Epsom, at the £9.30 cap.