You look under the pet section, it is on the upper left hand corner box. The ads sometimes get flagged for various reasons. Flagging removes the ads before you can see them sometimes. They get flagged if they say, for sale, adoption price, or the price is too high. they must say, rehoming fees and then only for the cost of vetting the pet.
As for what to look for, in the Jackson Michigan Craigslist, there is a spiny lizard and tank for a rehoming fee of $50. I think the subject line says Lizard looking for a new home. Something along that line. This guy has been selling lizards since early November, I think this is his last one. I have seen a ruby tail boa on the list. Other than that, nothing else.
You could also look under farm animals. Some try to sneak "for sale" pets there. You could also post a want in the wanted section.