I have been looking for best graphic card for my gaming Laptop. I know there are many companies which has produced large number of graphics card, I didn't find the best one which is most useful and handy to use.
I hate to be a negative nancy here, but this is something you probably should abandon for the following reasons:
Very few laptop models support swapping of the graphics. The only ones I'm aware of are Alineware's (which I believe have been proprietary in the past few generations) and Clevo (which includes other brands since they're a turnkey producer).
Replacement laptop graphics cards tend to be stupid expensive if you can find them. Although recent pricing has gone down, the last time I looked when the RTX 20 series were out, they were commanding over $1000 for a higher end one. And even before then, higher end ones were hovering well above their desktop equivalent.
Power and cooling requirements may exceed what your laptop is capable of.
If you have a Thunderbolt 3 port, you could get an external graphics enclosure, but a decent one with a power supply will run you at least $100-$150. And then you have to find a graphics card.