Without being able to examine the plants you have, I would call them the following:
#6: Salvia, possible Salvia rutilans (pineapple sage). Do the leaves smell like pineapple? Was it growing in an area where someone may have been gardening once? I'm fairly certain that this is a species of Salvia.
#7 and #8: Both are chickweed (Stellaria media). The species is highly variable in its leaf shape.
#9: Rununculus arbortivus. I have it in my yard, too.
I'm a wetlands plants biologist grad student and a landscape architecture grad student (although I really only know the native and invasive stuff). I did a seed bank study, where you see which seeds are in wetlands soils by collecting soil samples and germinating them (for 2 years in this case) in a greenhouse. Got to be pretty good at keying things out. Also got to be pretty good at tolerating tedium, too.
Based on the Texas database, I'd say that what you have there would be Salvia coccinea. Texas has lots of Salvinias. Beautiful plants. They grow very well into gardens and attract hummingbirds! See if you can take some of them home!
Alas, they aren't. Although I've tried the Ranunculus myself, since it grows in a damp/wet spot in my lawn. It disintegrated. But you could try it for fun. The others would definitely not survive.
Aquatic plants are really best found by visiting really wet spots, along the edges of ponds, streams, and in swamps. A great place to look can be where a wetland or stream crosses a powerline easement. Since the power people cut down the trees, full sun hits the water and lots of aquatics can grow. See if you can get a topographical map of your area, then look for streams crossing the power easements. Note, though, that topo maps don't show all streams and wet places, so be sure to read the topo lines to look for low spots. Then drive to the nearest road, and hike up the easement (with baggies in tow)! You might even find Lobelia cardinalis this way.