Single child

Align—Aligns a child within itself.
It takes a double value between -1 and 1,
for both the vertical and horizontal alignment.

AspectRatio—Attempts to size the
child to a specific aspect ratio.

ConstrainedBox—Imposes size constraints on its child,
offering control over the minimum or maximum size.

CustomSingleChildLayout—Uses a delegate function
to position a single child. The delegate can determine
the layout constraints and positioning for the child.

Expanded and Flexible—Allows a child of a
Row or Column to shrink or grow to fill any available space.

FractionallySizedBox—Sizes its child to a fraction
of the available space.

LayoutBuilder—Builds a widget that can reflow
itself based on its parents size.

SingleChildScrollView—Adds scrolling to a single child.
Often used with a Row or Column.