What video card should i buy for my optiplex 990?

If this is not the right section for this topic please move it im sorry..
Dell optiplex 990
Intel Core I5- 2500 CPU 4x 3,30GHZ Processor
Ram: 16 GB
Windows 10 64 bit home edition
Current video card: Intel HD Graphics 2000 2GB Ram
Im using my pc mostly for gaming and sometimes to watch tv shows and movies but i use it alot more for gaming.