As @JamesAllardice already said in the comments, the term harmony refers to all proposals for extending the current (ES5) language that meet the common goals of the TC39 committee.
Some of these harmony proposals are then selected and incorporated into the various specification drafts for the next version of the language (ES-next), which is currently ES6.
Those proposals that were not (yet) approved by the TC39 committee because of ongoing disputes ("disharmony") are called straw-man proposals.