Brown Recluse Spider
1/4″ to 3/4″ brown with a violin just behind the head pointing to the abdomen. The bite can cause necrosis (tissue death). More common in the south.
Long legs and small body. Commonly seen in basements and cellars. They pose no real threat.
There are many types of jumping spiders. The easiest identifier is that they jump! These spiders do have some venom but tend to run away from humans.
Females are 3/8″ brown to grey in color and hairy with markings or lines. Males are 3/4″. They do not make webs.