Question

What type of cloud is thin, high altitude and rarely produces rain?

Answer 1

Altostratus

Explanation:

Initially it seems like you are describing Cirrus, cirrostratus or cirroculumus clouds but you used the word "rarely". No cirrus type cloud ever produces precipitation.

"High altitude" would remove stratus.

Altocumulus Castelanus is not "thin" and normally altocumulus is not really either.

Altostratus is mid level cloud but since that can mean over 3 miles up I guess it can be considered "high altitude".