#6 Commercial cleaning.
A friend of mine started cleaning offices at night. Boring as it gets. Within two years he had 12 employees, three vans, and contracts with office buildings. The margins are insane because your main costs are labor and supplies, there’s almost no overhead, clients sign long-term contracts so revenue is predictable, and most people would never think to compete in that space because it doesn’t sound exciting. He now makes more than most of the tech startup founders I know and works about 20 hours a week managing the operation.
