The Baseball Bat is a blunt melee weapon that has appeared in every mainline Grand Theft Auto title since Grand Theft Auto III, making it one of the series' oldest and most reliable weapons, and it is due to appear in Grand Theft Auto VI. It has traditionally been the easiest weapon to get hold of, often placed at the player's safehouse in the earlier 3D Universe games and otherwise a common sight in the hands of gangsters, mobsters, and even ordinary civilians. An official Grand Theft Auto VI screenshot set in Port Gellhorn indicates the bat is carrying that reputation into the new game as well.
Weapon data via GTA Wiki (Fandom), CC BY-SA 3.0.