A man from the future comes back in time to prevent a scientist from conducting an experiment that will have the unforeseen consequence of sterilizing the soil.
A man invents a time mirror to display the past events of the person who looks into it. He pretends to be selfish so that a girl who is infatuated with him will profess her love to the self-sacrificing, but poor, man he has challenged to look into the mirror.
An alien from Ganymede gives a disk to a man hoping his curiosity will cause him to trigger a release of gas from the disk when he looks at it which will allow the aliens to invade easily, but the man tosses the disk into the river as he is blind.
Reprinted:
in Amazing Stories of Suspense (Alan Class, 1963 series) #134
When a detective falls into a coma, the fugitive that he has been assigned to apprehend finds that he cannot elude the man. The police chief is happy when the fugitive is delivered over to him and then shocked to find the detective just recovering from his coma.