First up is a local species of 'burrowing' wolf spider, Geolycosa missouriensis. These spiders sit in a burrow. They spend most of their time at the entrance only at night, but in the early morning they may still be there. Of course on approach they drop down, but if you keep still they come up again for pictures. This one may have recently established a new home since they normally have a small turret of woven grass at the top.

On another occasion I chose to take a picture at a lower profile with the camera mounted on a tripod.

Here is the rig used for that.

A few years ago (time flies!) I forced one out of its burrow to have a better look at these things. They are large spiders, I think with a leg span well over two inches. They dig their burrows with those big chelicerae.

The spider was of course put in a safe spot afterwards, and over night she would make a new burrow in the sandy soil.
Next up is a spider that was a puzzle at first. You can see it is eating a small jumping spider, and that turned out to be the whole point of it.

It was a male, and it had the "look" of an orb weaver so I did not expect it to be especially interesting. But I later learned from a comment online that this is what is known as a pirate spider. The particular species is Mimetus notius.
Pirate spiders are indeed in the orb weaver family, but they don't build webs. Rather, they are specialists at eating other spiders. It was quite a feat for this one to take down a sharp-eyed jumping spider, but they do have a specialized venom that quickly subdues spiders.
I have since found more of these, and can confirm the reports that pirate spiders will also take spiders that are in their own web. They do so by lurking around the periphery and getting the resident spider to come to come to it to investigate evidence that it has caught something. A simple bite to one leg and the other spider is done for. I've got pictures that show key parts of this story coming up in the queue.