Colossus (Piotr Nikolaievitch Rasputin) Created by Len Wein and Dave Cockrum, Colossus first appeared in Giant-Size X-Men #1 (May 1975)
Iron Fist (Daniel Thomas Rand-K'ai) Created by Roy Thomas and Gil Kane, Iron Fist first appeared in Marvel Premiere #15 (May 1974)
Doctor Strange Created by writer/editor Stan Lee and artist/co-plotter Steve Ditko, Doctor Strange first appeared in Strange Tales #110 (July 1963).
Thor Created by editor-plotter Stan Lee, scripter Larry Lieber, and penciller Jack Kirby, Thor first appears in Journey into Mystery #83 (Aug. 1962).
Omega Red (Arkady Rossovich) Created by Jim Lee and John Byrne, Omega Red first appeared in X-Men #4 (vol. 2, January 1992).
Elektra (Elektra Natchios) Created by Frank Miller, the character first appeared in Daredevil #168 (January 1981).
The Juggernaut (Cain Marko) Created by writer Stan Lee and artist Jack Kirby, The Juggernaut first appears in X-Men #12 (July 1965).
Jubilee (Jubilation Lee) Created by writer Chris Claremont and artist Marc Silvestri, Jubilee first appeared in Uncanny X-Men #244 (May, 1989)
Professor X (Charles Xavier) Created by writer Stan Lee and artist Jack Kirby, Professor X first appears in X-Men #1 (Sept. 1963).
Cyclops (Scott Summers) Created by writer Stan Lee and artist Jack Kirby, Cyclops first appears in X-Men #1 (Sept. 1963).