I passed my assessment on 16th of January (APC) so I want to describe a little bit as a help for others:
Interview & HR:
-4 forces of flight
-how lift is produced, how it can be increased, why high pressure and low pressure over the wing
-bypass engines
-de-ice and anti-ice systems
-tropopause height
-lenticular clouds
-how many seats in 737-800
A few more but I can't remember...
Simulator was pretty hard for someone without MCC like me.
Amended take off clearance, turns on different headings, position fix after some turns, intercept bearing to the station - hold over the station as in the plate, while in entry procedure the assessor told me that we have smoke in the back so I declared emergency to ATC and talked with my PM about decision in a normal way, not using standard MCC procedures. After that, he freezes the sim and moved me somewhere else for a position fix and again on ILS with enough distance from FAF, while going visual the ILS went down so we continued visual.
So my advice is to learn the briefing pack before, you will act as PM also and you should know the calls. Good luck!