I'm very new to game development and I find it very difficult to split the spritesheets available at opengameart.org. All of them are kind of jumbled together without any fixed grid.
The resource I learned from always used neatly assembled sprite sheets and Unity would have no trouble in automatically splitting them. But almost all are randomly placed and Unity cannot split them.
And below is the automatic splitting in unity:
How do you guys get the sprites from such spritesheets in unity? Some guidance would be appreciated.