What are the seven ways to reach first base without the benefit of a base hit?

1.Base on balls/walk
2.Hit by pitch
3.Error
4.Fielder's choice
5.Catcher interference
6.Called third strike not caught
7.Batted ball hits an umpire or runner before contact with a fielder

https://www.queryhome.com/sports/842/there-eight-baseball-player-legally-reach-without-getting

What about fan interference?

According to MLB rules, interference can only come from a player...fan interference in the case of a ball which may or may not have been a home run, for example, is ruled in the judgement of the umpire..usually a ground rule double.

If a fan interferes with a batter, time is immediately called...ala the "Kissing Bandit" incident when Morgana Roberts ran onto the field during an All Star game a few years back.