Take the example sentence:
Our offering includes widgets, gadgets, gizmos, and similar.
Would this be a correct way of ending that sentence, or do we need to add something more like:
Our offering includes widgets, gadgets, gizmos, and similar machines.
The latter sounds more correct to me, but I have no real reason for thinking so. Also, it is a little unfortunate having to sum opp all the examples' commonality in one word, when the purpose of having such a list in the first place is that it is hard finding a succinct common word.