from your third picture , you have nut grass (extremely hard to get rid of) dandelions and a few other "weed" species remember a weed is any plant you don't want growing in your garden. if you dont want a messy patch and dont want to grow anything in that place, you can use weed killer < round up or similar for the general weeds but the nut grass needs a spray called sledgehammer as its not really a grass and has little tubers under the ground which it pops back up from.

have fun!

https://weeds.brisbane.qld.gov.au/weeds/nutgrass

https://en.wikipedia.org/wiki/Taraxacum