finger – Prints user information in a human readable format.
pwconv – creates a shadow entry for an existing passwd user. Even if shadow entry is missing. Check out grpconv, pwunconv, and grpunconv for related functionality.
cut – Remove sections for each line of a file. (ex: cat /etc/group | cut -d: -f1,3)
newgrp – Log into a different group. UID stays the same but rights are changed to reflect new group membership. User must be a member of said group or a group password must be set for this to work. sg is an alias to the newgrp command.
passwd – Make changes to a users password. Actually this is a commonly used (i.e not misc) command but two options it has that I didn’t expressly know about. -l will lock a user account (when issued as root) and -S will display users password information (expiration date, warn before lock days, maximum number of allowed days with same password, etc.)
chage – Print or change a user accounts password information (expiration date, warn days, etc..)
wall – Sends a message to all system users. Root messages are the only ones displayed if user has blocked user-to-user messages.