If you do a Google search for Lasso Tool in Gimp
you will receive a few links and the first link in the search is from GIMP's documentation that shows the Free Selection Tool

Per an insert from Gimp
The Free Selection tool, or Lasso, lets you create a selection by
drawing it free-hand with the pointer, while holding down the left
mouse button (or, for a stylus, pressing it against the tablet). When
you release the mouse button, the selection is closed by connecting
the current pointer location to the start location with a straight
line. You can go outside the edge of the image display and come back
in if you want to. The Lasso is often a good tool to use for “roughing
in” a selection; it is not so good for precise definition. Experienced
users find that it is often convenient to begin with the lasso tool,
but then switch to QuickMask mode for detail work.
If I search for warp tool in Gimp
it provides a link to GIMP's documentation on the Transform Tools

An insert per Gimp
Inside the Transformation tool dialog, you will find eight tools to
modify the presentation of the image or the presentation of an element
of the image, selection, layer or path. Each transform tool has an
Option dialog and an Information dialog to set parameters.