You miss 100 percent of the shots you don’t take. Michael Scott of The Office famously said that, quoting Wayne Gretzky.

And a lot of teams on this list missed a lot of big shots in both trades and free agency. Whether it be general managers having last-second changes of heart, a union meddling, or some other reason, so many trades with legendary potential fell through over the years just as they were about to change history.

It’s always fun to think of what could have been, especially if your team hasn’t had much to cheer about over the last couple of decades. Had some of the trades on this list happened, they would have altered the history of leagues and franchises—turning losers into winners and winners into losers. Heck, the Montreal Expos might still be in existence if one of the trades on this list went down.

So let’s take a look at 14 trades and free agent signings that almost happened. You probably didn’t even know that most of these even existed. And a trigger warning for Raiders fans: They made the list three times. Narrowly missing out on three Hall of Fame quarterbacks.