let me before more specific, you could buy any old GPU from 2010 or even earlier and it would be more than powerful enough for what input it has. Search online and you will see how insignificant it is.
If you're buying a newish motherboard the onboard graphics will more than cope with Production related tasks, if you want more monitors... then you will need dedicated GPUs. buying a powerful graphics card is a complete waste of money for production.
I didn't have a dedicated GPU for over a year before i decided i wanted to get back into PC games, no noticable performance difference