Scratch test: use an empty beer/wine bottle but a piece of window glass will do fine.
Try to scratch the glass with the stone; if it leaves a streak the stone is harder then glass.
In this case; if the stone does NOT scratch the glass it is fluorite.
(But I'm guessing it is an amethyst as fluorite is usually more cubical.)
And yes there are very may different kind of agates.
Very nice and beautiful collection you have there.
The pink/peach druzy stone might be rhodocrosite. Or Druzy Rose Agate.