This is my second lot of Gradients they are few more but that is for some other day, here are about 14 new gradients for you, I need some patience and inspiration to make few so I might come back with more.
XAML:
<LinearGradientBrush x:Key\="CyanThemeBG" EndPoint\="0.5,1" StartPoint\="0.5,0">
<GradientStop Color\="#FFC6ECFE"/>
<GradientStop Color\="#FF003FFF" Offset\="1"/>
<GradientStop Color\="#FF37AFF9" Offset\="0.5"/>
<GradientStop Color\="#FF0076DB" Offset\="0.5"/>
</LinearGradientBrush\>
<LinearGradientBrush x:Key\="MagentaBG" EndPoint\="0.5,1" StartPoint\="0.5,0">
<GradientStop Color\="#FFFFCFFB" Offset\="0"/>
<GradientStop Color\="#FF930E2F" Offset\="1"/>
<GradientStop Color\="#FFFF659D" Offset\="0.5"/>
<GradientStop Color\="#FFC7174B" Offset\="0.5"/>
</LinearGradientBrush\>
<LinearGradientBrush x:Key\="BlackBG" EndPoint\="0.5,1" StartPoint\="0.5,0">
<GradientStop Color\="#FFE5E7FA"/>
<GradientStop Color\="#FF747C8D" Offset\="0.5"/>
<GradientStop Color\="#FF000000" Offset\="0.5"/>
<GradientStop Color\="#FF0F0F0F" Offset\="1"/>
</LinearGradientBrush\>
<LinearGradientBrush x:Key\="LightBG" EndPoint\="0.5,1" StartPoint\="0.5,0">
<GradientStop Color\="#FFE5E7FA"/>
<GradientStop Color\="#FFE3E6F5" Offset\="0.5"/>
<GradientStop Color\="#FFD5DBF1" Offset\="0.5"/>
<GradientStop Color\="#FFE1E4FF" Offset\="1"/>
</LinearGradientBrush\>
<LinearGradientBrush x:Key\="TealGreen" EndPoint\="0.5,1" StartPoint\="0.5,0">
<GradientStop Color\="#FFE3FCA9" Offset\="0"/>
<GradientStop Color\="#FF82B03C" Offset\="1"/>
<GradientStop Color\="#FFD8FA6C" Offset\="0.5"/>
<GradientStop Color\="#FFE0FF98" Offset\="0.5"/>
</LinearGradientBrush\>
<LinearGradientBrush x:Key\="CyanLargeBG" EndPoint\="0.5,1" StartPoint\="0.5,0">
<GradientStop Color\="#FF003FFF" Offset\="1"/>
<GradientStop Color\="#FF37AFF9" Offset\="0"/>
</LinearGradientBrush\>
<LinearGradientBrush x:Key\="MagentaLargeBG" EndPoint\="0.5,1" StartPoint\="0.5,0">
<GradientStop Color\="#FF930E2F" Offset\="1"/>
<GradientStop Color\="#FFFF659D" Offset\="0"/>
</LinearGradientBrush\>
<LinearGradientBrush x:Key\="LightLargeBG" EndPoint\="0.5,1" StartPoint\="0.5,0">
<GradientStop Color\="#FFE3E6F5" Offset\="0"/>
<GradientStop Color\="#FF9D9D9D" Offset\="1"/>
</LinearGradientBrush\>
<LinearGradientBrush x:Key\="GreenLargeBG" EndPoint\="0.5,1" StartPoint\="0.5,0">
<GradientStop Color\="#FF82B03C" Offset\="1"/>
<GradientStop Color\="#FFD8FA6C" Offset\="0"/>
</LinearGradientBrush\>
<LinearGradientBrush x:Key\="PurpleBG" EndPoint\="0.5,1" StartPoint\="0.5,0">
<GradientStop Color\="#FFB0B8FF"/>
<GradientStop Color\="#FF747C8D" Offset\="0.5"/>
<GradientStop Color\="#FF000000" Offset\="0.5"/>
<GradientStop Color\="#FF151733" Offset\="1"/>
</LinearGradientBrush\>
<LinearGradientBrush x:Key\="DarkGreen" EndPoint\="0.5,1" StartPoint\="0.5,0">
<GradientStop Color\="#FFB0FFC4"/>
<GradientStop Color\="#FF5D645F" Offset\="0.5"/>
<GradientStop Color\="#FF000000" Offset\="0.5"/>
<GradientStop Color\="#FF15331F" Offset\="1"/>
</LinearGradientBrush\>
<LinearGradientBrush x:Key\="DarkYellow" EndPoint\="0.5,1" StartPoint\="0.5,0">
<GradientStop Color\="#FFF3FFB0"/>
<GradientStop Color\="#FF63645D" Offset\="0.5"/>
<GradientStop Color\="#FF000000" Offset\="0.5"/>
<GradientStop Color\="#FF2F3315" Offset\="1"/>
</LinearGradientBrush\>
<LinearGradientBrush x:Key\="DarkGrape" EndPoint\="0.5,1" StartPoint\="0.5,0">
<GradientStop Color\="#FFFFB0FD"/>
<GradientStop Color\="#FF8D7485" Offset\="0.5"/>
<GradientStop Color\="#FF000000" Offset\="0.5"/>
<GradientStop Color\="#FF331532" Offset\="1"/>
</LinearGradientBrush\>
<LinearGradientBrush x:Key\="DarkBrown" EndPoint\="0.5,1" StartPoint\="0.5,0">
<GradientStop Color\="#FFFFEAB0"/>
<GradientStop Color\="#FF8D8774" Offset\="0.5"/>
<GradientStop Color\="#FF000000" Offset\="0.5"/>
<GradientStop Color\="#FF332A15" Offset\="1"/>
</LinearGradientBrush\>
Usage Syntax:
Its very simple just use above lines in App.xaml under <Application.Resources> and then you can use them any where in your project
<Rectangle ... Fill="{StaticResource DarkBrown}"/>