Most of my series can be read separately without spoilers. The Changeling Chronicles and Legacy of Flames series take part in the same world, but in different locations with no overlap between the two series. I generally recommend starting with the Changeling Chronicles, my first series set in that world.
The Thief's Talisman takes place a year after the Changeling Chronicles. It stands alone, but there are some spoilers for the Changeling Chronicles series in the later books.
The Darkworld, Alliance and Indestructible series all take place in different worlds with no overlap. :)
Why aren't your books available on other sites aside from Amazon?
At the moment, my books are only available on Amazon because they have to be exclusive to be part of Kindle Unlimited. They can be read on any device with the Kindle app.