If I remember correctly:
- Captain Picard
- Commander Riker
- Lt.Commander Data
- Commander Troi
- Lieutenat Worf
There is no designated structure following 2nd officer on the USS Enterprise-D. The chain of command that follows is dependent on the captain or commanding officer at the time. Lt. Worf becomes the 1st officer for Data in "Gambit", however Data selects Worf over La Forge. Likewise in "Best of Both Worlds" Captain Riker selects Commander Shelby to serve as his First Officer, but he could have selected Data or Worf for the position.
There are other members of the enterprise crew who also hold high ranks, and do command shifts on the bridge from time to time. Dr. Crusher and Counselor Troi both carry the rank of Commander (by series end). Neither is likely to be selected for full command unless circumstances are extreme (such as Troi taking command during "Disaster" or Crusher taking command in "Descent"). However, they can pull rank when necessary, as Troi did during "Disaster" over Ensign Ro.– The preceding unsigned comment was added by 188.8.131.52 (talk).
The lists at the top doesn't take into account that Troi, LaForge or Dr. Beverly Crusher aren't line officers, so generally they'd would be on the list after Lt Worf, if their primary duties permit them to take command. Because of their primary duties though, more junior officers probably fill that role during normal duty shifts. General Rule of thumb, those officers wearing Command Red or Operations Gold would be serving as Commanding Officer before those in Science Blue / Teal. TrekFan1984 Ends (talk) 13:28, March 18, 2017 (UTC)