I saw all these guys play, though only a couple of times seeing Ted in his last year. I think Williams, Brady, and Russell deserve special status cause of how long they were great and how ridiculous their accomplishments were. It's one thing to be great for 5 years, and another to be great for 15 like these 3 were.
Russell my childhood idol won 11 of 13; Brady's 10 SB appearances and 7 rings just as impressive. Williams is now almost criminally underrated. He sacrificed what would've been among his 5 most productive seasons to the wars. He likely would have broken 700 homers and had at least 1 ring. Also amazing is that he CAME BACK from several years of hellish war without missing a beat. He was a premier fighter pilot by all accounts, and also one of America's all-time great outdoorsmen. He was THE authority on both hitting and flyfishing, so together with fighter pilot that's 3 of the hardest things to do in life. Long 6'3" athlete with that "greatest generation" mentality and an outsized personality a-la-Bird. He was a superhero really.
Bird, Orr, Pedro and Papi were comets who soared the highest but for a much shorter period. All were arguably "the greatest ever" at one point or another. Papi maybe a little less so, but he was so dominant in those World Series postseasons that he belongs in this tier - just absurdly clutch HR's.
Then there's stars like Yaz, Bourque, Havlicek, Cousy, Heinsohn, Hannah, Seymour, Sam Jones, Cowens, Espo and others who were also HOF greats but somehow all lower than 7th on this list. Yaz won the triple crown in one of the greatest seasons of all time, Cousy was the Bird of the 1950's, and Hannah is probably the greatest OG in history.