Your options in Ontario are much more limited then many in the United States have since many of the plant poisons readily available here have been banned for homeowner use there. Many of us do not consider any of the clovers to be "weeds" and do nothing to control them since they do help place nutrients in the soil and the flowers help feed the pollinators. The most common plant poison, 2,4, D with Dicanbra, has been banned in Ontario.

I don't recognize the plant, but it looks like it's spreading by underground runners, and that is never a good sign. I think that you are going to have to dig up the whole area and pull out the roots; if you decide to do that, I highly recommend a garden fork rather than a spade or shovel - just my experience. I do think that you should take one of the close-up pictures you've got at imgur and post it on the Name That Plant forum, because quite often you need to know who your enemy is to eradicate them.

24 in one post is a very tall order but I'll start you off. It is generally easier for us if plants are posted one or two at a time. And please don't make us keep clicking to open images. Post them in the body of the message. 1. Taraxacum officinale - Dandelion 2. A member of the Rubiaceae - possibly Galium aparine - Goosegrass or Cleavers. 3. Stellaria media - Chickweed 4. Mercurialis perennis - Dogs mercury 5. Geranium species - which one depends a lot on where it is growing. 6. I am going to stop here because I have the feeling I am doing your homework for you. For future reference please always tell us where in the world the plants are growing and give an indicator of scale. Also it is far easier to id a growing plant than one which has been pulled up and is beginning to wilt.

Chickweed, Stellaria media, a cool weather annual weed. Very easily pulled up but do it before it goes to seed!! Also edible if you care to get rid of it that way :-)