Horses usually denote the understanding of the spiritual things and also relates to intellect/intelligence.
In Native American mythology, the lizard is the dreamer. Dreaming of a lizard, therefore, is a sign that your dream was an important one and reveals a lot about where you're coming from, where you're going, and how best to get there. (Could this relate to your foster family, maybe?) In order to get this information, look to the other symbols in your dream.
What did I see this morning on my walk? A huge gaggle of geese, loudly announcing their presence.