The Royal Numismatic Society has kindly made several of their Special Publications free to download as pdfs:
including (just some examples:)
- SP 7: Roderick T.
Williams, Silver Coinage of the Phokians (1972)
- SP 29: Richard
Ashton, Studies in Ancient Coinage from
Turkey (1996)
- SP 40: Kenneth A.
Sheedy, The Archaic and Early Classical Coinages of the
Cyclades (2006)
- SP 41:
Seaby and
Ireland, A
Catalogue of
Ancient Coins in the Cabinet of Sir Rodger Newdigate of Arbury Hall, Warwickshire
- SP 42: Jennifer
Warren: The Bronze Coinage of the Achaian
Koinon(2007)
- SP 43: Ann
Johnston,
Greek Imperial Denominations, ca 200-275: A study of
Roman Provincial Bronze Coinages of
Asia Minor (2007)
- SP 44:
Casey,
Arslan, et al,
Sinope: A
Catalogue of the Greek,
Roman and
Byzantine Coins in Sinop Museum (
Turkey) and Related Historical and
Numismatic Studies (2010)
- SP 47 and 49:
Curtis, Askari etc:
Sasanian Coins: A Sylloge of the
Sasanian Coins in the National Museum of
Iran, vols 1 and 2
- SP 50: Humphris and Delbridge, The Coinage of the Opountian Lokrians (2014)
- SP 51: Bennett, Elite Self-Representation on the
Provincial Coinage of
Asia 31 BC – AD 275 (2014) (This is an indepth study of magistrates on coins of
Asia Minor, but it is not a
catalog per se).
Coin Hoards Volume 1 (1975), Volume 2, (1976), Volume 5, (1979)
Make sure you have enough room on your harddisks - many of the above are a Quarter-Gigabyte in size (250 Mb+)
The download links can be found in the list here:
https://numismatics.org.uk/society-publications-2/special-publications-and-coin-hoards/