This is a repository that doesn't want to be complete: there are much more interesting collections around the internet. There are also very good sites that maintain a list of old programs, like this one, where you can discover how many Reversi / Othello programs were written during the 80s / 90s for every kind of consolle and personal computer. Browsing unmaintained repositories on
internet, it's clear that this is just a minimal selection of the great
number of programs written in the 90s. By that time, anyway, I remember
that I made a good selection of the strongest ones.
So why this section? I just added a few programs I had on the hard disk since very long time, good programs that were written generally for DOS and should not be forgotten. As I said, this is not a complete list, I myself have also other ones that maybe one day will be added.
Please note that many DOS programs need libraries, variables or something else to work on modern computers. If you have trouble, consider making a Virtual Machine and start it from a virtual old DOS floppy (or install an old DOS or Windows system on it). It could run better.
BmOth 3.1 beta is one DOS program I wrote in 1995, as new version for my old program written in 1991 or so. It's in beta version and will always remain so. It's strong enough to train a learning player, nothing more, but I'm proud of it because I included the alpha-beta search in the algorhythm without ever knowing it had already been invented by someone else.
This is a DOS experiment I did and of which I'm very proud. It includes many thousands of matches played on ios (Internet Othello Server, now ggs), and lets the user analyze the statistics about the openings, baseed on players skills and even minimaxing the result.
Watch out: the program is about 60MB when unzipped.
Isaac 5, by Luigi Lamberti, is available also on his personal site: http://www.luigilamberti.it, where also an archive of matches and a book is downloadable. It has been a very useful and handy tool for Italian players, and, although it has been surpassed by stronger program, it still is one of the most handy programs available.