Doing sweat equity is definitely  prohibited. 

However, I did mention Robert Kiyosaki's book, If that is prohibited I'm apologize for that.

I understand the concern if one of your tenants is Airbnb'ing his/her unit under your lease which prohibits it.

No more write offs of gambling losses, employee expenses, tax prep fees, investment fees, etc.529 State Education Accounts can now be used for primary and secondary schools in addition to higher education and can now also be used for religious and other private schoolsYou can no longer unwind a Roth ContributionSo many other nit-picky changes that will apply to very few folks, but will be important to get right for those to whom it does apply.Just a clarification: Recharacterizations of Roth conversions are now prohibited.

The CA law for home daycare overrides any lease clause that prohibits a home business.

The ACH system does not prohibit partial payments, or encourage them.

. - in my neighborhood, it's a Chesapeake that has bitten a few kids and attacked other dogs, so maybe they belong on the list of prohibited breeds.

If a tenant is damaging property or causing a hazardous condition, that would be something you can enforce (I presume your state laws have prohibitions in this regard, or your lease agreement as well).

During the trial, the judge and psychologist witnessed there was no proof of intent for such material to be used but federal law prohibits the handling of such.

It says "Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof".