Abandonware

Abandonware is a product, typically software, ignored by its owner and manufacturer, which can no longer be found for sale, and for which no official support is available and cannot be bought. (Wikipedia)

• The Internet Archive is actually a great place to start your search. Check under the Software section.
• Torrents are also a good place to look for things. Searching for "<xyz> torrent" on a search engine or the Internet Archive are good ways to find torrent links.
• Always virus check downloads. Virustotal.com is a great free service to scan downloads across nearly all popular anti-virus software.