This list is being compiled by asdudevil, BigBert, Morg and myself in collaboration. It is intended to suggest some variants which have relatively standard rules and no more than seven players, but which are known to be good quality variants and well-worth playing (and GMing).
In alphabetical order:-
Ad Arma
African
Baltic
East Asia
Five Italies
Heptarchy
Pericles
Renaissance
Sail Ho!
South American Diplomacy
Zeus