The plural is a normal one, horoscopes.
That is the correct spelling of horoscope (astrological analysis or forecast).
The plural way to spell studio is studios.
The plural is cherries.
The plural is resources.
The plural is cantaloupes.
The plural is hooves.
The plural is roses.
The plural is "emeralds."
The plural of "bridge" is "bridges."
Trout is plural
The plural of "frill" is "frills".
The plural is "recesses".