The Hall of Flame is a leaderboard on the Blaseball website that lists every incinerated player.  Within Blaseball, the Hall of Flame might be considered an afterlife for Blaseball players, as evidenced by Jaylen Hotdogfingers being required to literally leave the Hall in order to return to the league.
Blaseball fans can pay tribute to any incinerated player by viewing their player profile in the Hall of Flame and giving an offering of peanuts. As of the time of writing, there are no known consequences or effects related to tribute.
On Season 7, Day 100, The Monitor made its first appearance, revealing itself to participants of Blaseball at the end of a front page takeover by The Shelled One. The Monitor mentioned following Jaylen Hotdogfingers "from the hall, from the trench," confirming the connection between the Hall of Flame and The Hall Monitor.
During the Season 7 Election Results, The Monitor appeared again and offered to "make [the fans] a deal" to "see your friends" in exchange for "tiny eggs?" After this appearance, the Hall of Flame was available on the site for the first time, featuring the leaderboard of almost every incinerated player.
Briefly in the time immediately after the Hall of Flame became available, there was a blue line (similar to the red idolatry line) located under the 14th place ranking. It disappeared shortly afterwards. When asked to comment, Umpire Sunman denied its existence by saying: "LINE? DIDN'T SEE A LINE." Its purpose is unknown.
Following the attack from THE SHELLED ONE'S PODS on Day X and the Season 9#Election Results, the mysterious blue line appeared in the Hall of Flame again, underneath the top 14 incinerated players. Its purpose remains unknown.