The following screenshots show several gameplay Crusader abilities and new monsters, Enchanting UI, Nephalem Rifts & Rift Guardian bosses.
In addition, a few Reaper of Souls new locations such as the Westmarch Chapel, Bloodmarsh, and the Pandemonium Fortress and their respective monsters.
Check out far more on the Blizzplanet’s BlizzCon 2013 Coverage page — screenshots, videos, interviews and panel transcripts.