Graphics Card: For Gaming PC Only or Any PC?

I have a windows 11 PC unit that I use for my work and gaming. I would like a better visual, and more realistic gaming experience when playing my RP and adventure games. What color and quality graphics cards are recommended if I do not currently own a specific gaming PC?

Thanks, I appreciate the feedback. I am still learning about the technological aspect of gaming ;-)

My Best,

WarriorsCreed