I think what made Queen special in comparison to other bands is a) their vast diversity of songs, from stadium rock to operatic indulgence to pop, and b) they never suffered from the "our heyday was album 2 and 3, now we're just putting out meh albums to support our tours". Essentially every album of theirs featured a hit (in order: Keep Yourself Alive, Father to Son, Killer Queen, Bohemian Rhapsody, Somebody to Love, WWRY/WATC, Fat Bottomed Girls, Another One Bites The Dust, Under Pressure, Radio Gaga/IWTBF, A Kind of Magic/WWTLF, I Want It All, Innuendo). They managed to stay musically relevant for almost 20 years, very few bands manage that.