The ads can be whatever you want. With a few rules.

The ads cannot look like exactly like and be mistaken for adsense ads.

The ads must be family-friendly and offer legal things. Both of
those at the same time. Legal is not always family-friendly.
Guns and beer are legal, but against adsense TOS. Many people
forget to read all the rules. Many other things are also banned.
People just don't read the list. Anything like a PTC or surfing
reward program is also not allowed as well. People don't read,
put up some blog posts or ads on that, and BINGO. Their
number comes up and they swear they did nothing wrong.

Paul