Free agent signings occur during every NFL season. While there are always big name players with high expectations, sometimes the diamonds in the rough end up being the difference makers. Here are five of the best free agent signings during the 2021 NFL season.Best free agent signings of the 2021 NFL season#1 - RB James Conner, Arizona CardinalsArizona Cardinals running back James ConnerThe Arizona Cardinals signed James Conner to a 1.75 million dollar contract prior to the 2021 NFL season. He ended up being one of the biggest bargains of the year for his massive contributions. He scored 15 rushing touchdowns, the second most in the entire NFL, on his way to a Pro Bowl selection.Cardinals Nation@CardinalsNatio3#AZCardinals RB James Conner is Heading to the Pro Bowl this weekend Congrats @JamesConner_11:25 AM · Jan 31, 2022100643#AZCardinals RB James Conner is Heading to the Pro Bowl this weekend 🙌🙌🙌🙌 Congrats @JamesConner_ https://t.co/AGmU6foLYV#2 - DE Trey Hendrickson, Cincinnati BengalsCincinnati Bengals defensive end Trey HendricksonWhen the Cincinnati Bengals signed Trey Hendrickson from free agency last year, it went a bit under the radar. He ended up being one of the best edge rushers of the 2021 NFL season, recording a massive 14 sacks. His contributions helped improve the Bengals defense, which is a big reason why they made it all the way to the Super Bowl.