Commodore Software Exchange BBS v2.6 - Simple, straight forward BBS made for the exchange of wAr3z!  When you start it up, it asks you for a few passwords (a backdoor password even) and a logon and logoff text file.  Bing, bang, let the software reign (rain)?

Seriously though, I did several GoogleFu moves to find out more info and came up with zip. 

Elite Exchange One BBS (EX1-BBS) by Steven Prothero (Ironfeather - 1988 / 1989) - Here is a quote from the Author in 2021 as found on the BBS Documentary site -  "EX1 BBS Software was sold nationwide for $25 (included all future updates free and instruction booklet), version EX1-185 was released on "qlink" and BBSs as a shareware version. Created in BASIC(blitzed) & ML By Stevyn Prothero aka IronFeather. I took ideas from C-net (like mci commands), ideas from COLOR64, Ivory, etc. I had a "spec" file it loaded first and that contained all the settings, I tried to make everything an "option". This of course confused many people, and made setup a workout. I also had some template files for questionnaires, new user apps, etc. Towards the end i added ANSI translation & was converting "adventure" like games over to work with it. Dam, if I had more tyme i would tweak it even now ;)".

Here is a link to the manual.

After a little more searching, it turns out Steven (IronFeather) still runs a BBS of sorts (A web forum) called the Iron Feather Journal.  

G.S.T. BBS v6.0 by Gut Soft - Written by Guy and Serge Turgeon. Nice little (complete) BBS system that can run off a single 1541 floppy drive. Docs are on the disk but you'll need to run the 'GST BBS Edit' first to create some relative files the main program needs. Big thanks to DLH of bombjack.org for finding this.

Found this great blog post with more info about the BBS and instructions on how to set it up in VICE 3.6.

NC-BBS v2.0 otherwise known as Not Commline BBS by Stephen Chan is a very simple Blitzed compiled BASIC BBS for the Commodore 64.

Network BBS by Sean D.L. McVeigh (March / April 1990) - Ran across this BBS tonight which I haven't seen before.  Seing as it doesn't have a version number, I suspect it was a one time release.  There is some documentation on the disk, and this is a working setup (written mostly in BASIC) so jump in and check it out.  

Plato BBS is a very simple system written mostly in BASIC, but you never know, it may be all you need or want, so check it out.

I found this rather obscure BBS program for the Commodore 64, written back in 1986 by Charles Van Lingen, while rooting around archive.org.  Although the program disk is labeled as v4e, the program itself shows v4c as you can see from the screen shots.  The program is mostly written in BASIC, so it's highly customizable and might be useful for learning purposes.  One thing to note as pointed out in the archive.org posting is that there is likely a backdoor in the system that allows the bypassing of passwords.

Here is a link to the Toronto CBM mailing list from the peson who uploaded this to archive.org.  There is some additional information in the thread you might find interesting.

Ultra-Com BBS v1.3 (Also known as UCBBS) by Pudwerx (Released 1990) - From the little research I've done, my guess is that this is a heavily modded / improved Ivory BBS.  There is a small program on the disk that goes over the BBS features both from the user's perspective and the sysops. 

Thanks to DLH over at Bombjack for providing the disk.