Books and journals may go out of print and be difficult to locate, but web pages as the primary medium of the digital age are even more elusive. They appear and disappear as those who create and maintain them lose interest and commitment, and their URL addresses change as they are moved from ISP to ISP. Trying to maintain a useful list of web site links is frustrating.
With that caveat, the following are current as of early 2019:
Typical of the official fan club sites is this one for the “Hanshin Go-Tora Kai” 阪神伍虎会
Certainly the most useful (Japanese-language) web site for the late 1990s and early 2000s was 「げんまつWEB タイガース歴史研究室 猛虎歴研」. This began in 1995, and the site name and URL changed several times. It disappeared and reappeared twice and now exists at that URL as an inactive archived site. The webmaster is anonymous, but has been a thorough and conscientious amateur historian of all things Hanshin Tigers for decades. The coverage is encyclopedic–biographies of players, coaching staff, front office, and corporate executives, salary figures, spring training sites, nicknames, and much more. I am not vouching for accuracy, but where I have been able to double-check, I have never found a mistake.
For English-language fans, by far the best current site is “The Eye of the Tiger,” devoted to “Hanshin Tigers English news.” It is news and much more, and I highly recommend it. It is produced by Trevor Raichura, a Canadian ex-pat who has lived and worked in Japan for over twenty years. He moved to Kansai some five years ago and quickly became a Tigers fan. His site is a massive labor of love, notable for two features. First, he goes beyond typical fan interest in providing schedules, rosters, game commentaries, information about the stadium and club history, and help in the logistics of obtaining tickets and enjoying games there. He does a regular podcast and has an archive of previous shows. Moreover, his fluency in Japanese means that he is conversant with the media, articles, and books on Hanshin, and he has a book review section of the site that has thoughtful commentary on some of the key works about the Tigers. He also writes a regular column for one of the sports dailies and has an archive of English and Japanese versions.