Wikipedia defines abandonware as "computer software that is no longer sold or supported, or whose copyright ownership may be unclear for various reasons."
There is a lot of this stuff around. In fact there are whole websites dedicated to it.
For example there's VetusWare, a site that has a huge range of older commercial apps ranging from Word 6 to AutoCad R13.
Then there's Abandonia, a site that specializes in classic DOS games.
Visting these sites is a pleasant trip down memory lane even if you don't find something you want.
Also be aware that while these programs are free they are not necessarily freeware or free of copyright. So if you are planning to use anything
commercially check with the original developer first.