That? component identification

I suspect the first one is a light detector of some sort.

From the size of its leads, the second one looks like a Zener diode, but for sure it's a diode of some kind.

The third one is a 4.0 MHz ceramic resonator with internal caps for use in a Pierce oscillator.

From the "BYV" legend on the fourth one, it's a high-speed rectifier of some sort. The rest of the legend would probably single it out.

The fifth one, a transistor? a dual diode? ???

The sixth one is a 10pF 1kV ceramic capacitor

Views showing more legending would be helpful.

The board designators seem to be following IEEE STD 315 (kind of).

CR or D: Crystal rectifier (Diode) T: Transformer.

My guess is that this is a common mode choke on the power supply lines.