Eight different men caught passes for the NFL Champion 1964 Cleveland Browns. In fact, five of them (Paul Warfield, Jim Brown, Gary Collins, Ernie Green, and Johnny Brewer) accounted for over 95% of the team's receptions. They had a league-high 28 touchdowns through the air in 14 games.
In their Week 15 game at New England in 2013, nine different Browns had receptions. For the season, 17 players had at least one catch (8 WR, 3 TE, 6 RB). Cleveland led the league with 681 passing attempts and almost certainly in the number of plays with unique passer-receiver combinations.
The obvious conclusion? Fire the coach.