While the best teams are usually built through the draft, hitting pay dirt in the free agent market can put NFL teams over the top. These 25 NFL free agent signings stand out as the best in history.
The Chiefs signed Mathieu to a three-year, $42 million contract to replace safety Eric Berry. Mathieu led a maligned Chiefs defense to its first Super Bowl victory in nearly 50 years and was named MVP by his teammates, after recording four interceptions and 75 tackles during the regular season.
Philadelphia brought in Foles to back up second-year quarterback Carson Wentz in 2017. The move seemed somewhat inconsequential at the time, but it helped lead Philadelphia to its first-ever Super Bowl victory. Foles started the final three games of the regular season and went on to win Super Bowl MVP. The following year, Foles went 4-1 as a starter during the regular and started again in the playoffs for the Eagles due to more injuries to Wentz.
The 2012 NFL offseason was also the Peyton Manning sweepstakes, as the elite quarterback went looking for a new team after sitting out the 2011 season with a neck injury. Led by the recruitment efforts of John Elway, Denver got its Man-ning. Manning put up spectacular numbers in his first three seasons with the Broncos, including a record-breaking 2013 season, but his one Super Bowl victory with the franchise came in an injury-plagued 2015 season as a result of Denver's elite defense.
Smith was a good player during his first seven seasons in Cincinnati, but he turned into an elite one after signing a massive six-year, $45 million deal with the 49ers in 2008. During his seven seasons in San Francisco, Smith made five Pro Bowls and recorded 43.5 sacks while missing a total of two games. He also appeared in one Super Bowl with the team.
The greatest free agent signing ever? Brees joined the Saints in 2006 as the team returned to New Orleans following Hurricane Katrina. Coming off a shoulder injury, Brees went from being a good quarterback in San Diego to an elite one under Sean Payton with the Saints. Since the signing, Brees has made 12 Pro Bowls in 14 seasons, won one Super Bowl and led the NFL in passing yards seven times.
Coming off an injury-ravaged 2005 season in Oakland, Woodson signed a seven-year deal with Green Bay in his age-30 season. He would be well worth the money, making four Pro Bowls in his seven seasons with the Packers, with a staggering 38 interceptions. He moved to safety later in his time with the Packers and finished his career with Oakland.
It looked like Warner could be finished after a year with the Giants in 2004, settling on a one-year deal with the Cardinals. He wasn't much better in his next two seasons with Arizona. However, the former Rams MVP started to turn a corner in 2007 and led the team to a Super Bowl appearance the following year. After another good season in 2009, Warner retired from football.
Harrison wasn't much of a prospect early in his career, going through stints with the Steelers, Ravens and Rhein Fire. He eventually went back to Pittsburgh in 2004 but didn't work his way into the lineup regularly until 2007. That season started a streak of five straight Pro Bowls, with Harrison winning the 2008 Defensive Player of the Year after recording 16 sacks. He also won two Super Bowls with Pittsburgh.
After winning Super Bowl XXXV in Baltimore as Jamal Lewis' backup, Holmes signed with the Chiefs in 2001. He was expected to fight for snaps with Trent Richardson and Co. in the revitalized offense under head coach Vermeil but turned into a superstar almost immediately. His first three seasons in Kansas City rank among the best ever by an NFL running back, as he gained more than 2,100 yards from scrimmage in each season with a total of 61 touchdowns. Holmes was voted the 2002 Offensive Player of the Year. He played only 19 more games over four years following 2003, struggling through injuries.
The Chiefs made the controversial decision of sticking with Elvis Grbac in 1999 despite Gannon's success in Kansas City. Gannon signed with the rival Raiders in his age-34 season and made four straight Pro Bowls. He also won the 2002 MVP, leading the league with 4,689 passing yards, but Oakland was blown out by Tampa Bay in Super Bowl XXXVII.
Woodson had 10 seasons in Pittsburgh and one year in San Francisco, but he became a free agent in 1998 after the 49ers cut him. After eventually signing in Baltimore, he helped complete one of the greatest defenses in league history. Woodson made four straight Pro Bowls and won Super Bowl XXXV in 2000-01 for one of the best defenses the NFL has ever seen.
Bill Parcells coached Martin in New England during the running back's first two seasons and managed to bring him to the Jets in 1998. Martin signed in New York as a restricted free agent and would spend the rest of his career in New York. He rushed for more than 1,000 yards in seven straight seasons with the team and led the league with 1,697 yards rushing in 2004.
Warner agreed to a futures contract with the Rams in 1998 and became a backup quarterback for the team after playing in NFL Europe. He barely found the field in his first season but was forced into a starting role the following year after Trent Green suffered a season-ending knee injury in the preseason. The rest is history, as Warner went on to lead the Rams to the Super Bowl and win two MVP Awards in six seasons with the team.
New York signed Mawae away from Seattle after his fourth season, and he became a staple on the team's offensive line with six straight Pro Bowl appearances from 1999-2004. He also never missed a start during his first seven seasons with the team before suffering a triceps injury in 2005, his final year with the team.
Jacksonville signed McCardell to a lucrative contract in only its second season as a franchise, and it turned out to be a perfect fit. McCardell had his first 1,000 yard season in 1996 and would surpass that mark four times in his six years with the Jaguars. The wide receiver duo of McCardell and Jimmy Smith is still remembered as one of the best of the '90s.
Few free agent signings in history got better immediate returns than Buffalo's signing of Paup in 1995. He recorded a league-high 17.5 sacks in his first season with the Bills, winning Defensive Player of the Year after five years in Green Bay. Paup had a total of 33 sacks in three seasons with the team.
After five seasons in Atlanta, Sanders joined the 49ers and won Defensive Player of the Year after recording six interceptions and returning three for touchdowns. The two-sport star also helped lead the 49ers to a Super Bowl victory.
After going undrafted in 1978, Moon became a star in the CFL with five consecutive Grey Cup victories. He entered the NFL in 1984, signing with the Oilers and eventually proving he could play in the league. He spent 10 years in Houston, leading the league in passing yards twice and winning the 1990 Offensive Player of the Year.
Plunkett revitalized his career with the Raiders after San Francisco released him in 1978. He spent two years as the Raiders backup but replaced the injured Dan Pastorini in 1980. Plunkett would go on to win 1980 Comeback Player of the Year and lead his team to two Super Bowl victories before his career concluded following the 1986 season.
Seth Trachtman is a fantasy sports expert and diehard Kansas City Chiefs fan still hoping for a Super Bowl win during his lifetime. He doesn't often Tweet, but when he does, you can find him on Twitter @sethroto.