Team Fortress Classic was published by Sierra Studios in 1999. This logo appears in the boxart of the physical version of the game. Additionally, a variant of the logo appears in the disk of the game. The words "Team Fortress" use the font Impact, otherwise the word "Classic" uses the font Haettenschweiler instead.
The current Team Fortress Classic logo, featured on the Steam store, is different. The main difference being the word "Classic", as it does not use the previous font and instead use Impact like the other words.