Which type of additional training should I get as a driller to boost my career?

for a starter we can say IWCF level#4 (Supervisor level)

Rig Pass.

Control of wells in drilling operations.

Well control in workover and reconditioning operations.

Control of wells in coil tubing units.

Well control with IWCF, stuck pipe and rigger training

As a driller you must have knowledge about your drilling machine. What type of drilling bits are best, how to control water loss.

The most important thing is to control the Pressure while drilling.

for a starter we can say IWCF level3 drillers 

certaficate

IWCF and IADC supervisor level

IWCF Level 3, and STUCK PIPE COURSE

well control training course