Since before 1994 there were more than 7 rounds in the NFL draft I am only picking players drafted in 1994 or later. The following are noteworthy players drafted in the 7th round.
C Tom Nalen (1994, pick 218)
RB Jamal Anderson (1994, pick 201)
WR Donald Driver (1999, pick 213)
DT Jason Ferguson (1997, pick 229)
TE/LS Brian Jennings (2000, pick 230)
WR TJ Houshmandzadeh (2001, pick 204)
DT Raheem Brock (2002, pick 238)
WR Patrick Crayton (2004, pick 216)
RB Derrick Ward (2004, pick 235)
CB Reynaldo Hill (2005, pick 218)
CB Cortland Finnegan (2006, pick 215)
WR Marques Colston (2006, pick 252)
RB Deshawn Wynn (2007, pick 228)
As for the best ever of these guys the obvious choice is Center Tom Nalen. He is the most accomplished of everyone here. In the future guys like Houshmandzadeh, Marques Colston or Patrick Crayton may overtake him but until then Nalen reigns supreme. A close second is Donald Driver and in third I would put TJ Houshmanzadeh.