This is true. I have a game called “City Limits” which is the exact same as monopoly except the “Chance” cards aren’t called chance and don’t look the same and the properties are more realistically priced (20k, 40k, etc) with less realistic monetary denominations (20k, 40k, etc)
Essentially, the items trademarked are: Railroads, Chance, Property names, Go to Jail, Names of Properties and Utilities, Community Chest, “GO”, Physical look of money, play pieces, and cards.
The other main legality is “for profit.” Just like music and videos, you stay under the radar of the companies by simply distributing it to a small group for free. As long as you don’t use the above trademarks, you have a 99.9999% chance of not being noticed.


