The pictures on this blog post are all my own, taken through a microscope, sorry not all of them are the best quality. But at least I don't have to collect links to sources!
Mitochondria- the largest dark dots are the nucleus, but you can see lots of little dark purple spots which are the mitochondria. This is from a prepared slide of an onion root with a special stain for seeing mitochondria, and a brown stain for cell walls.
These look quite blurry, it's just because there are multiple layers of cells superimposed on one another. This was a hand mounted water weed leaf. All the little green speckles everywhere are chloroplasts- the organelles which house thylakoids for conducting photosynthesis. :)
These are like chloroplasts, but they are not green. They are still colored though, hence the name chromo ("color") plast. You can make out the little orange specks from a carrot:
And tiny red specks from a tomato:
Amyloplasts- these are a type of plastid that contains starch storage. The tiny purple granules are the ones. They're only purple because a stain was added to this potato so you could actually see it.