Not all small parties that I see on the Wikipedia list even run in the elections? That’s weird, makes it look like they aren’t even trying. I think they should attend symbolic. Like “hey we are here. We exist” Just being on the Ballot also makes a difference.

Most of them don't. Many of them that do run are only state-level parties, not national. Third parties are very splintered in this country, other than the Libertarians and Greens, who, like I said, aren't very serious. Only 4 out of 47 seats in my state, for example, were contested by the Libertarians and Greens.