Firestar brings heat and flight, Iceman brings cold and ice-slides, and Spider-Man brings the web-lines and the wisecracks. In a fight it's a near-perfect spread: fire above, ice below, and a nimble acrobat swinging between them. They cover each other's blind spots and finish each other's plans, which is exactly why fans have loved the combination for decades.
In the mainstream comics the three didn't share a house, but Marvel has tipped its hat to the trio many times -- most directly in a 2006 reunion one-shot. Firestar later fought beside Spider-Man in big New York crises like Maximum Carnage. However they come together, the tone stays warm: this is Spidey with real friends.
The Amazing Friends began on television, not the page. In the 1981 NBC series Spider-Man and His Amazing Friends, Peter Parker shared a home near Empire State University with two college friends, Bobby Drake (Iceman) and Angelica Jones (Firestar), plus Aunt May and a little dog named Ms. Lion. The three decided to fight crime together as the Spider-Friends. Firestar was created specifically for the show -- Marvel wanted a fiery hero but couldn't use the Human Torch at the time, so a brand-new character was invented. She proved popular enough that she was introduced into the comics a few years later, first appearing in Uncanny X-Men #193 in 1985.
Firestar and Iceman remain active, well-liked Marvel heroes -- Firestar has moved between the New Warriors, the Avengers, and the X-Men, while Iceman continues as a core X-Man and has headlined his own solo series. The classic Spider-Friends trio is treated as a fond, nostalgic team that Marvel revives now and then rather than an ongoing group. (A separate 2021 Disney Junior preschool series, Marvel's Spidey and His Amazing Friends, borrows the name but uses different characters -- Spidey, Ghost-Spider, and Miles Morales -- not Firestar and Iceman.)
Firestar is Angelica Jones, a mutant who generates and controls microwave radiation -- letting her fly and throw blasts of intense heat and flame. Iceman is Bobby Drake, one of the original five X-Men, who can freeze moisture in the air to make ice, ride ice-slides through the sky, and turn his own body to solid ice.
Both were created young and stayed among Marvel's most likeable heroes. Firestar went on to join the New Warriors and later the Avengers; Iceman has been an X-Man for his whole career. Paired with Spider-Man as the Spider-Friends, they became a beloved, kid-friendly trio that introduced a whole generation to Marvel's teamwork spirit.