"Life After Life, Death After Death"

In Poul Anderson's "The Voortrekkers" (Explorations, New York, 1981) (see previous post), the transferred neural patterns visit:

Sirius, which has no planets;

Tau Ceti, where they send organic bodies to explore a planet;

Sigma Draconis, where the organics meet intelligent beings;

36 Ophiuchi B, where they explore a planet;

82 Eridani, where a substance in native food releases "'...an enzyme which destroys niacin in the bloodstream...'" (p. 172) so that the organics cannot survive.

Over the centuries, they give Earth:

the ability to travel swiftly between stars in organic bodies and to colonize uninhabited planets;
an end to sickness, insanity and old age;
cultural input from many races, leading to an unending renaissance;
vast wealth for each individual;
growth towards wisdom and an end of strife.

They visit Earth, return to space and remember their original lives.