Players signed to futures contracts typically aren't ever big contributors, but they're not without value. Consider that Josh Andrews and Ed Reynolds were among nine players who signed to futures contracts following the 2014 season. Both players contributed on the 53-man roster in 2015.
A quick breakdown on each player:
Brett Boyko - Signed with the Eagles as an undrafted rookie free agent. Philadelphia gave him a decent signing bonus. Will compete for a depth spot at tackle in the summer.
Malcolm Bunche - Some people, myself included, thought Bunche might sneak on to the 53-man roster. Instead, he was waived in final cuts. Bunche showed some nice potential in the preseason. He could reasonably compete for a guard spot in the future.
Brandon Hepburn - Spent most of the 2014 season on the practice squad. Extra body at linebacker.
Freddie Martino - Has some NFL experience with the Falcons. Martino joined the Eagles during training camp this year but picked up pretty quick. He had a nice summer, finishing preseason with 100 yards and one touchdown on 10 receptions.
Kevin Monangai - The Villanova alumnus rushed for 126 yards on 21 carries (6.0 average) in the preseason.
Travis Raciti - Undrafted rookie free agent who played at defensive end and nose tackle.
Deontae Skinner - Spent some time on the New England Patriots active roster. Versatile linebacker.
Note that the NFL roster limit expands to 90 in the offseason. For a more detailed explanation on what a futures contract is, see this explanation. (Source)
Basically, when a player is signed to "reserve/futures" contracts means they are being signed for the upcoming season even though that season does not officially begin until the official start of the league’s new year as outlined by the NFL. Only players who were not on any NFL team’s active roster when the previous season ended are eligible for these types of contracts. If they were under contract, then they would remain so until the league’s new year starts. Players who were on practice squads at the end of the season are eligible to sign with any team. Hence the reason that you see many practice squad players being signed by their current team for the upcoming year to a reserve/futures contract. That way the team can continue to work with a player they’re familiar with and hopefully get them ready for an eventual roster spot on game day.