Note that some software may be listed under retail games, even if a demo version has been released.
See the World of WarCraft page for information about downloading World of WarCraft.
Patches to all official versions of DOOM (both Shareware and Retail) will be made available at this site. The page related to shareware version of DOOM has information about that specific release.
Files for the full version of the game (and other releases in the WarCraft 2 series) are available at the WarCraft II page.
Apparently (from very old War2 fan page) there was a http://www.blizzard.com/war2demo.htm but today that redirects to a 404 page at http://www.blizzard.com/us/war2demo.htm. Apparently (from another old Warcraft 2 page) there used to be links for getting the demo at http://www.blizzard.com/us/library/war2ibm.htm and http://www.blizzard.com/us/library/war2mac.htm
Archived version of home page for Warcraft 2 Demo for IBM-PC shows the page linked to ftp://ftp.blizzard.com/pub/demos/war2demo.exe and to the original version of the following: archived version of home page for Warcraft II Split Demo for IBM-PCShareware version Apparently was at http://ftp.blizzard.com/pub/demos/war2demo.exe and ftp://ftp.blizzard.com/pub/demos/war2span/war2dem?.zip (unverified/untested URL: http://ftp.icm.edu.pl/packages/coast/games/blizzard/warcraft/war2demo.exe ) (Other files there were authentic) Possibly http://www.giffer.com/public/dos/pgam4/gam40116.htm (war2dem?.zip in Files/) ftp://ftp.cdrom.com/.2/games/dos/wc2/war2demo.exe
archive of old Warcraft II Demo for Macintosh home page had the following two download links (with no explanation on their contents being different, so presumably they were the same) : ftp://ftp.blizzard.com/pub/demos/Mac_Warcraft_II_Demo.sit.hqx http://blizzard.com/bin/macwar2_sw.sit.hqx It also linked to archive of the Warcraft II Split Demo for Macintosh home page (which was found from archive of old Warcraft 2 Macintosh page) showed 10 downloadable files under ftp://ftp.blizzard.com/pub/demos/macwar2span/
The following has not been tested/verified.
WarCraft II demo for Macintosh found from VintageWare (for Apple computers) which also discusses two major incompatibilities: fast systems, and the ability to see the CD in Mac OS X. The HQX file found has been stored locally as w2macdem.zip as an untested, unverified file.
http://ftp.blizzard.com/pub/starcraft/demos/SCDemo.exe http://ftp.blizzard.com/pub/demos/Starcraft_Demo.sit http://ftp.blizzard.com/pub/demos/Starcraft_Demo.sit.hqx
This is a unique game similar in style to Breakout and Arkanoid. Some people don't like it simply because it seems too easy when playing the demo. There are in fact some levels that are very easy, thanks in part to sometimes ridiculous powerups such as a combination of thrusters which allow the paddle to move vertically (as well as horizontally) and dozens of very large balls. However, it can be more challenging when use of thrusters is expected to achieve a difficult angle for one last brick. Level 55 is also quite tough.
The original shareware release was made for the DOS platform, although registering that version may not be easy or possible any longer. The game has since been released by DotEmu for Windows XP/Vista, Flash, iPhone, and iPod Touch. These new releases are available from KryptonEgg.com. Krypton Egg for Win32 has been available for $9.95.
Teamtris was a shareware release by Cintric Systems, as noted by Youtube video: Teamtris (1992).
There is also: Teamtris.net, which released a DOS game much more recently. This version supports up to four players, and different shapes of pieces.