They could make then but they don't so there is none. There is a adapter that allows the user the use of a normal desktop card but renders the laptop non mobile. In the the vast majority of laptops and tablets you will not be able to upgrade your graphics card, it is simple as that and it just plane sucks.
Do you mean a low profile video card which is about half the height of a regular video card.
This is about lap top graphics but a kit can be purchased that plugs into the mini-pcie slot that allows any desktop card but renders the laptop no longer mobile. Basically the laptop becomes useless in that respect as for the card it will end up needing its own psu and at very reduced performance will work but the onboard gpu will be disabled so the only real use to this is if the screen or the onboard gpu died. They could make them in mini pci-e format but they won't be cheap and requires a custom gpu (MCM) but may be tricky to cool as well power. This is the fatal flow in laptops and tablets.