Item Scroller is a Minecraft mod that adds various convenience features for moving items inside inventory GUIs. Examples are scrolling the mouse wheel over slots with items in them or Shift/Ctrl + click + dragging over slots to move items from them in various ways etc.
Item scrolling is basically what the old NEI mod did and Mouse Tweaks also does. This mod has some different drag features compared to Mouse Tweaks, and also some special villager trading related helper features as well as crafting helper features.
For more information and downloads of the already compiled builds, see https://www.curseforge.com/minecraft/mc-mods/item-scroller