Ok first off you need to match the B series engine to a B series gearbox i.e y21/s4c etc. your D series EJ9 gearbox cannot be reused and also will need a set of B series driveshafts with 32mm outer cv joint.
Other bits you need,
All B series mount brackets (cambelt side, gearbox side, rear L bracket, front lower torque mount brackets)
You can reuse your ej9 mounts if there in good condition.
Shift linkage.
B series radiator + piping if not included with B series engine.
Engine wiring loom + ecu
All new fluids, coolant, gearbox oil, engine oil etc. It would be a good time to change the timing belt also unless you know exactly when it was last done on engine.