.....as I understand the brightness means danger, however the colours are very attractive and appealing to the human eye.....
Never eat (my) strawberries, raspberries, redcurrants, cherries, plums, red apples etc....
Lots of poisonous stuff.. in varying degree. One of the worst is lilly of the valley - not that it looks edible. Cherry laurel is a classic (cyanide?) as are yew berries (taxins). Poisos may also be benficial if used correctly.. the obvious examples being opium=> morphine and foxgloves for heart drugs. Perriwinkle is another good one .. contains alkaloids for vincristine and vinblastine... both anticancer drugs.
You can find lists of the more common poisonous plants via google