The MLB offseason has been painfully slow when it comes to actual transactions, but at some point it's going to pick up and players will start to be signed. In the meantime, we're going to run through the positions and rank the available free-agent options. For one huge list, we have a free agent tracker with every position included. We've also ranked the best options at catcher, first base, and middle infield.

Now, let's run through a poor third-base class. 

Top free agent catchers
Mike Moustakas Free Agent 3B
Moustakas is a two-time all-star coming off a season in which he hit 38 home runs and showed he was completely over the ACL injury that cost him almost all of 2016. Oh, and he turned 28 in September, meaning he's relatively young for a free agent. Despite some shaky seasons earlier in his career, Moustakas has developed into an above-average hitter, evidenced by his 117 OPS+ since 2015. Opinions on his defense vary, but make no mistake: he's going to be handsomely compensated this winter by a team seeking a new starting third baseman. 
Todd Frazier Free Agent 3B
The biggest knock against Frazier is his age. He'll turn 32 before the season begins, and there's a fair chance his contract runs into his mid-30s. Some team will pay for those plausibly lean years in order to get Frazier in their lineup for the next season or two, during which he seems likely to be an asset. Frazier is a league-average hitter or thereabout, but one who is capable of playing a respectable third base while launching 25-plus homers a season. That's a solid player.
Eduardo Nunez Free Agent 3B
Nunez isn't a skilled defender; he doesn't walk; and he offers limited power. What Nunez does is put the ball in play and leverage his wheels to hit for average and steal bases. Add it all together, and you have a player who excels in ways that don't necessarily appeal to teams in this day and age. He'll get a multi-year deal anyway, but he's not going to be as well-received as he would've been with more traditional front offices in place.
Yunel Escobar Free Agent 3B
Escobar is a bit like Nunez, in that his game is predicated on putting the ball in play and he's a former shortstop whose defensive metrics paint him as a below-average third baseman. Escobar hasn't hit double-digit home runs since 2011, and he's always worn out his welcome quickly. Nonetheless, he's historically been about a league-average hitter and the aforementioned flaws could leave him available for less than his market value.
Brandon Phillips Free Agent 3B
Everyone from this point forward had at least one miserable extended stretch of play. Phillips' came after joining the Angels in a late-season trade, as he managed a 75 OPS+ in his final 24 games. To Phillips' credit, he still posted an OPS+ above 93 for the third consecutive season. At some point, he's going to fall to pieces for good. For now, he should get the chance to prove he can provide some offense as a 36-year-old.
Trevor Plouffe Free Agent 3B
To the right set of eyes, Plouffe looks like a worthwhile buy-low candidate. Prior to last season's poor mark (61), he'd posted an OPS+ of 90 or higher in each of his six big-league seasons. The catch is Plouffe was so bad after being acquired from the Athletics by the Rays , hitting .168 with limited power output in 42 games, that it's reasonable to wonder if the shoddy play was an aberration or the beginning of the end for the 31-year-old. Some team will find out.
Jose Reyes Free Agent 3B
Reyes salvaged a disaster season by posting an .828 OPS in the second half. He's a substandard defender who was clearly stretched at shortstop. The domestic violence allegations against Reyes shouldn't be forgotten, either.
Conor Gillaspie Free Agent 3B
Gillaspie, who is now on the wrong side of 30, was a league-average hitter as recently as 2016. He's always struggled against lefties, and his glove doesn't earn him a lot of slack. Even with the weak class, he doesn't merit more than a minor-league deal.
Darwin Barney Free Agent 3B
A relatively fruitful 2016 campaign at the plate aside, Barney has always been a glove-first player. Like Pennington below, Barney is more of a middle infielder. He gets the nod over Pennington because he's younger (having the cooler name doesn't hurt). 
Cliff Pennington Free Agent 3B
We told you it was weak. Pennington has played more middle infield during his career, so it's a stretch to label him a third baseman. His 64 OPS+ over the last three seasons suggests it's a stretch to expect offensive output from him, too.