There are just a few flip-flop boards in the system:
A18B3 and A19B3: These boards contain a set/reset flipflop with AND/OR inputs and a delayed output. The delayed output allows the circuit to be employed as divider: the output can be connected to the input as long as the signals are ANDed with pulse shorter than the delay time (1 microsecond or less). The entire computer is built using a single type of flip-flop!
I miss type A219A5: toggle flipflop.