Most Sprite Sheet Exporters support putting gaps between the individual sprites but the aesprite sprite sheet importer doesnt account for that or have a way of importing sprite sheets with gaps between the sprites of a fixed or irregular size.
One work around is to put the initial x offset to be negative, but that still doesnt help with irregular gap sizes.
In addition the sprite sheet importer doesnt have a way to filter out tiles with nothing in them other than manually deleting them.
Ideally, the sprite sheet importer should just detect continuous non transparent pixels as sprites and either let the width and height be variable to fit each one or just center them in bounds based on the largest sprite in the sheet. Thats how it works in Unity’s sprite sheet importer at least.