Here is what I found as well as links to websites where available:
Counterpoint became part of NCR in 2011 and is still around and being updated (but with a fairly small install base of around only 7000 stores according to NCR): http://www.counterpointpos.com/
SBS Keystroke is very much around with current updates: http://www.keystrokepos.com/
RegistWare (sometimes called RegisterWare) has changed hands several times but is currently being offered by discountPOS (note that the RegisterWare website appears to be dormant): http://www.registware.com/
Regit 2000 also is "around" but unclear how much updating has been done: http://www.pos-warehouse.com/regitdownload.htm
SMS QuickSell 2000, QuickSell HQ and QuickSell Commerce where all acquired by Microsoft and re-branded/updated as Microsoft Retail Management Systems (RMS) Store Operations and Headquarters (HQ). These programs are alive and well with a very large global installations base (upwards of 30,000+ stores) and one of the largest customization/add-on catalogs available today (giving the software unique adaptability for multiple retail verticals): http://www.microsoft.com/en-us/dynamics/rms-overview.aspx
Cougar Mountain has also survived and updated their point of sale software: http://www.cougarmtn.com/accounting/retail/POS-Accounting-Software
The General Store is alive and kicking as well: http://www.thegeneralstore.com/
Despite what appears to have been a very long bankruptcy, Retail Pro has new ownership and will likely release new features and enhancements over the coming years (which which bring a sigh of relief to the 52,000 stores using Retail Pro globally): http://www.retailpro.com/
The website for ComCash is functioning but has a copyright date of 2010 and the last "tweet' from ComCash was over four months ago: http://comcash.com/index.php
Liquor Store Controller is now LiquorPOS: http://www.liquorpos.com/liquorPOS.html?gclid=CJak1Pzr6LQCFYl7QgodTF8ASg
Those are the main programs that I came to know very well 14 years ago - nice to see that nearly all of them are still around! Be sure to comment in case I missed any retail point of sale programs that survived the 90's and 2000's.
Are you in the US and in need of no cost retail point of sale advice? I'm happy to help and can be reached on my cell at 208-340-5632 (mountain time) or via email at email@example.com.