Here's how I found hundreds of dropshipping stores:
I used a technology lookup platform called Builtwith to find stores using dropshipping apps like CJDropshipping, Spocket, etc.
I went through reviews of dropshipping apps (on Shopify App Store) to find the stores that left a review for the app. (Only merchants who have used the app can leave a review)
I looked for dropshipping stores that are currently on sale on platforms like Flippa and Exchangemarketplace.
I found trending products on Alibaba and Aliexpress. Then, I threw those products' images in the Google image search to find stores selling the same product without even changing the images.
And, of course, I did the basic Google search.