I loved Mike Pritchard when I was a kid, so I'll dispense with the preamble and just point out that he was really good for a three year stretch in Atlanta. That's enough to make him the best player ever to wear #35 for the franchise, without question.
Pritchard began his career with the Falcons in 1991, reeling in 50 catches for 624 yards and two touchdowns in his rookie year. The next season was arguably his finest in the NFL,as he put up 77 catches for 827 yards and five touchdowns, following that with a fine 74/736/7 season in 1993. He was gone after that year, sadly, and went on to have a productive but not stellar career with the Broncos and Seahawks.
He was inarguably a possession type receiver, but he was a nice fit for those early 90's Falcons teams, and a player I'll always remember fondly.
His only real competition for the gig comes from William White, a safety who capped his career in Atlanta in 1997 and 1998, playing pretty well in both years as the team's 16 game starter.
Tip of the cap to Pritchard!