Can probably not max out every single game(will be able to in many), but is a great video card for the price i think.https://uk.pcpartpicker.com/part/msi-video-card-n760tf2gd5oc
MSI twinfrozr gtx 760, 170£. Great price. doesnt max out the budget though.
Radeon hd 7950 from sapphire. My friend has this, and it owns whatever games he plays(mostly shooters).https://uk.pcpartpicker.com/part/sapphire-video-card-111961920g
R9 280 https://uk.pcpartpicker.com/part/powercolor-video-card-axr92803gbd5t2dheoc
Basically rebranded 7950.
All of these around 200£