Roper iPoll
Roper iPoll is a strong alternative to Gallup Brain. Search for questions by keyword. Microdata for more than 2,800 individual Gallup public opinion polls, from 1936 to mid-2015, may be available for download from the Roper Center for Public Opinion Research, Cornell University. This microdata includes the monthly-rotation Gallup Poll Social Series polls and also other Gallup polls.
Polling the Nations
Polling the Nations offers responses to surveys conducted in 100+ countries going back to the 1980s.