Name / People / Contacts list that doesn't involve typing to start searching
The ability to choose from a list of people and their titles. doesn't need to be always there but something you can enable.
When starting a chat or group chat it's good to have a list to browse to make sure you've included all parties. typing it out takes your mind away from the task at hand.
Also for those who are new and do not know how to spell a name correctly can be problematic.
Directories are always a feature that should be included.