Another example is the nuucp account, which uses /usr/lib/uucp/uucico as a login shell.
Many users have favorite shells, for example the bash shell, that they might want you to install. As with any other software, make sure it comes from a reputable source. (bash shell is public domain software .) You may wish to back up the system completely before installing the shell, then monitor the system closely for a while to be sure there are no problems with the shell.
For security reasons, you should not blindly accept compiled binaries and install them as login shells on the system (or anywhere else on the system, for that matter). Start with the source code for the shell, make sure there are no security holes in the code, then compile it for your site.
Note that special shells should be located in a file system that is always mounted before users log in to the system. If the file system that contains a login shell is not mounted, people who use that shell cannot log in to their accounts.