I think these are databases that they acquired when they bought British Origins, but now you can search and view them on findmypast:
London Apprenticeship Abstracts 1442-1850
Surrey and City of London Livery Company Association Oath Rolls 1695-6
Archdeaconry Court of London Wills Index 1700-1807
(If you want to view a will which is listed in this index, it should be available in the London Probate records on ancestry, though of course FMP don't tell you that!)