Unrestricted free agency is going to look and feel a bit different this year.First of all, there isn’t much in the way of talent bound for the open market, and even more names are likely to disappear from the various UFA lists between now and July 1. Secondly, virtually everybody has $15 million or more in available cap space to spend.Gone are the days when cap space alone would be the most important factor shaping unrestricted free agency. Now, player preference and open auctions are more likely to determine outcomes.For the rebuilding Vancouver Canucks, free agency is still a critical avenue for adding talent, even if the club’s ambition to qualify for the playoffs will take a back seat over the near term.In a world with rising cap space, after all, teams are unlikely to pay rebuilding sides to take on their undesirable assets the way they used to. If Vancouver is going to accumulate the assets this rebuild requires, then it’ll have to find new ways to create exchange value, and the open market is going to be a key — if thorny — avenue to mine.With this in mind, having broken down some trade candidates that would fit in with the Canucks’ rebuilding posture earlier this week, let’s spotlight 15 UFAs (and a bonus consideration) for the Canucks to consider when the market opens.Sign any credible NHL-level UFA still unsigned by July 5Some of the players bound for the open market on July 1 will have to wait to secure their NHL opportunity. Some of those players will be very good, and some of them are probably even on this list.And while they wait, their cost and bargaining power will recede. Their potential utility, however, will not.Last summer, the Canucks opted out of the Jack Roslovic sweepstakes in August, but Vancouver would’ve been much better off signing the skilled veteran winger, who ended up being productive for the Edmonton Oilers.This summer, value has to be everything for the Canucks. There are no perfect targets, no particular needs.There is simply the question of: “Who can we sign, and for what amount, that can potentially turn into a useful trade asset for us?”And the best way to answer that question, more reliable than any underlying metric or scout’s opinion, is to simply scan the list of available unrestricted free agents on July 5, and go about making the cleanest, most affordable bet still available.1. Ryan Shea, LHD, Pittsburgh PenguinsShea enjoyed a breakout campaign with the Penguins as a 29-year-old this season, highlighted by 35 points and a ridiculous plus-30 rating that you just know some NHL general manager out there is itching to pull out their owner’s chequebook to buy.Boxcars aside, Shea is a sharp two-way defender. Though his production was inflated, partly by bounces and partly by playing with Kris Letang, his underlying form was legitimately good both with and without his star partner.I think he has the opportunity to pay off something like a Sean Walker-level $3.6-$4 million contract over a multiyear term, and so long as the bidding doesn’t get too silly, he should be a top free-agent target for a lot of teams, even including the Canucks, given the exchange value that reliable defenders tend to hold. Doubly so if Vancouver subtracts further from its blue-line group.2. Beck Malenstyn, RW, Buffalo SabresMalenstyn is a top-end skater with local ties who plays smash-mouth, in-your-face hockey. What else do you need to know?The 28-year-old hails from Delta, B.C., and would bring some desperately needed toughness and speed to the Canucks lineup. He’s not the most skilled offensive player, but he’s defensively reliable and a solid penalty killer.If Vancouver could keep the term down, overpaying for Malenstyn on a short-term deal would be a sharp way to entertain the fans, acquire a solid person and create future asset value during the rebuild.3. A.J. Greer, RW, Florida PanthersGreer might be one of the league’s most underrated players.The 29-year-old winger is legitimately excellent defensively, he’s physical and he scored 17 goals this season, putting together a late-career offensive breakout in a platform year for the Panthers.Greer is unlikely to be an every-season 15-goal scorer on his next contract, but what he’s sure to do is play physical hockey and solid defence. And even if his goal totals were inflated by a shooting percentage binge, it’s worth noting that Greer is legitimately good and has often seemed like a player who could do more if given a larger opportunity. Then, when he was finally given one, he did more with it.At 6-foot-3 and nearly 225 pounds, Greer would be a jumbo-sized addition to Vancouver’s top-nine forward group, and despite his age, he’s one of the most straightforward value plays available on the open market, provided the Canucks manage the term (and overpay on the salary) to land him.Colton Sissons had eight points in 22 playoff games for Vegas this season. (James Guillory / Imagn Images)4. Colton Sissons, C, Vegas Golden KnightsSissons, fresh off a strong showing for the Golden Knights in the Stanley Cup Final, is an ideal free-agent target for a Canucks team that’s going to need a dependable penalty-killing ace and faceoff specialist while blooding young centres like Braeden Cootes during the next handful of rebuilding seasons.