Marvel Chronology Project

Original X-Men 1 has a short sequence of the five original X-Men fighting Eel and Plantman on grounds before they get sent to an alternate universe.

Eel and Plantman team up to assist Nefaria in X 22-23 in Washington D.C. and don't team up again until the 1970s. My first intent was to find a spot during X 22-23 but I didn't find one. So the best spot is right after X 23 while they are still in Washington DC, as the X-Men try to round up the villains on the run.

Suggested additions:
ANGEL III/WARREN KENNETH WORTHINGTON III
X 23
OXM 1
X 24

BEAST/HENRY "HANK" PHILIP MCCOY
X 23
OXM 1
X 24

CYCLOPS II/SCOTT SUMMERS/"SLYM DAYSPRING"
X 23
OXM 1
X 24

EEL II/LEOPOLD STRYKE
X 23
OXM 1
AF SPEC

ICEMAN/ROBERT "BOBBY" DRAKE
X 23
OXM 1
X 24

MARVEL GIRL/JEAN GREY SUMMERS/"REDD DAYSPRING"
X 23
OXM 1
X 24

PLANTMAN/SAM SMITHERS
X 23
OXM 1
SUB 2