Используйте приложение APKPure
Историческую версию Flutter Widgets можно получить на Android
Компиляция нескольких виджетов флаттера из официальной документации
This app contains a collection of several flutter widgets from the official documentation. I use this app to visualize the components, memorize them easily and later be able to replicate that behaviour in the apps I want to create. A similar app helped me a lot when I was learning ionic, so I hope this app helps other people to learn flutter widgets.