Here are few samples for Xamarin.Forms buttons.
<Button Text="Button A" />
<Button
Text="Button B"
CornerRadius="20" />
<Button
Text="C"
CornerRadius="30"
HeightRequest="60"
WidthRequest="60" />
<Button
CornerRadius="45"
HeightRequest="90"
WidthRequest="90"
ImageSource="image.png" />
<Button
BackgroundColor="Transparent"
ImageSource="image.png" />
What kind of button is missing that you would like to see here too? Let me know.