In game shows, typically it's the announcer's job to describe the prizes. This is done in one of two ways: The announcer might identify the prize and then give a description, e.g., "A new car!!!" <insert audience "ooohs"> "The Pontiac Bonneville, with custom headlamps and hubcaps....". Other times, the host identifies the prize, then the announcer describes it, possibly with cueing from the host, e.g. on LMaD, Monty would show a prospective contestant a canister of coffee filters, "...and Jay Stewart will tell us about it." The old school Newlywed Game did this as well, where Bob Eubanks would say "Your very own, brand new, washer and dryer!!" at which point Johnny Jacobs would expound.
But how often did it happen where the host himself described the prize in its entirety?
The only show I remember where this was routinely done was during the later years of NBC Concentration, where Bob Clayton himself would do the complete voice-over for the description of the Chevy Nova between games. The Chevy was awarded to any contestant who called a double Wild Card, regardless of whether they won that particular game. I think the descriptions of the prizes won "on the board" were done by Wayne Howell.
I also have a distant memory of an early-70s daytime Dating Game episode in which Jim Lange might have described the prize for the couple, which involved a trip on B.O.A.C. airlines (now part of British Airways). I only remember that because I remembered a different gameshow announcing a prize trip on that same carrier, but they pronounced it "BO-ack", whereas Jim spelled it out.