There are some lovely free books for your Kindle here at mobileread:
https://www.mobileread.com/forums/ebooks.php?forumid=128
But no starter pack. I don't know of any starter packs as such. But I'm sure you can get some help on what books to start with in the Reading Recommendations forum here:
https://www.mobileread.com/forums/forumdisplay.php?f=24
Enjoy your Kindle