I mean,
here's the list of all free agents back to pre-2011. It'll also show you all free agents into the future. The resources are all right at your fingertips and most definitely don't require "research"
Going back to when the Pirates should have been trying to win (I guess we can say pre-2013?), the top available 1B (based on salaries received) who have been available to everybody have been:
Pre-2013: Kevin Youkilis, Lance Berkman, and Mike Napoli all got 1 year deals. Jack Hannahan is the highest paid guy who got a multi-year deal, and he got a 2-year deal.
Pre-2014: Mike Napoli, James Loney, and Justin Morneau all received shortish deals (2-3 years) and all were traded/released prior to the end of their deal. The Pirates traded for Ike Davis in an effort to fill 1B this year -- he wasn't great but they at least could release him easily.
Pre-2015: Mike Morse got the largest deal among 1B. The Pirates acquired him last year during the trade deadline and paid the 2nd year of his 2-year contract during this season. Hanley Ramirez was signed as a 3B/LF and is transitioning to 1B, and was the highest paid 1B this offseason if he's included.
Pre-2016: Chris Davis got a massive deal for some reason. Mike Napoli and Steve Pearce (former Pirate prospect) were the next 2 highest paid players at 1B, and they received 1-year deals.
I strongly advocated (on the scout.com board) for the Pirates trading Joel Hanrahan at the trade deadline in exchange for Chris Davis back when he was with the Rangers. I was told I was a Pirates hater and that they needed to be buying at the deadline because they were really close to getting to .500 and you can't just gamble on unproven guys when you have a closer that's getting the job done.
What happened prior to 2008, I don't care about. Different regime. They tanked intentionally beginning in 2008, so I'm fine with them not signing any serious free agents. It kind of defeats the purpose of tanking.
Saw an interesting feature on 538.com and they tracked all of the teams through the years by how good/bad they were relative to the league. During the entire Littlefield era, the Pirates were never the worst team in baseball. That's absolutely terrible management for a front office claiming a "five year plan". The Pirates didn't ACTUALLY tank until around 2009/2010 -- which is what they should have done all along under Littlefield.
Edit: In the interest of full disclosure, pre-2012 had the following "1B" available:
Albert Pujols for his massive deal (which still has 5 years left after 2016)
Prince Fielder for his massive deal (which still has 4 years left after 2016)
Michael Cuddyer, Carlos Pena, Luke Scott were the next 3 highest paid players.
So, I mean, yeah -- 1B has been an issue but I hardly think the Pirates have been worse off with their internal options relative to the players available. Anybody out of that 1B pool who wound up being good was a dumpster dive, and by rule we cannot give the Pirates credit for going cheap and buying low on a guy.