two strings to one's bow

have a lot of/a few/several etc. strings to one's bow (Also have another/more than one string to one's bow — иметь выбор между двумя средствами; иметь какое-л. средство про запас

Meaning: to have an additional interest, skill or qualification which you can use if your main one cannot be used (BrE & AuE):
If you can teach English as well as yoga, it's another string to your bow. ... это тебе (дополнительный) плюс; ты имеешь дополнительное преимущество

I enjoy my work, but I'd like to have another string to my bow in case I lose my job.(CALD)

He's a trained lawyer and he does pottery classes in the evenings - he has several strings to his bow.

See also [arrow in one's quiver (an)]
[ace in the hole]
[туз в рукаве]