Alternate source of income

I work in Tech. The sword is always hanging. Have been in this industry for 15 years now. I was wondering if I am fired and I am unable to find a job (I feel I am becoming obsolete day by day), what could be my options? The only thing which comes to my mind is becoming a Cab driver. What else one can do to generate an alternate source of income? If my question lacks information please let me know. Really looking forward to the experts here to provide some guidance. Thank you!