List all of your friends on BattleNet, sort by btag or game/client, or selectively exclude/include certain Blizzard games. For example, if you play Overwatch in addition to WoW, you might turn that on to find someone to game with.
Starting with 0.250, if you mouseover a character icon, you are given the option to click on it and pop it up, enlarged, in a mini-window.
Switch your IC/OOC status in supported RP addons (MRP, TRP3) with a single click from your friends list.
Starting with 0.250, if you mouseover a character name, you're given the option to click on it and open their profile in your RP addon (TRP3 or MRP).
The first page of the options menu. Version 0.260.
Search for your friends, online or offline, by their name, friend note, and other fields.
Second page of the options menu, for selecting columns. Version 0.260.