I've been making use of the handy bag in Uncle Genny's 100% Organic and Free Range Modpack and find it very useful. I have an idea for an enhancement that would make it even more useful, IMHO. I would like there to be a void upgrade or option to prevent additional stacks of an item from being created when the stack limit is reached. This would make it function a bit like a /dank/null, allowing for the storage of many of an item while voiding any excess. This could be implemented on a per bag or per memory card basis. If you wanted to make this option harder to get, you could possibly limit it to only the top tier of memory card.

Personally I don't really like the idea of adding voiding functionality to the bag or the cards. IMO it's adding too many completely different capabilities to a single item. And also that's kind of what the Nullifier item is for.

However I think I might add a new separate pickup mode where it would only fill already existing stacks on the card, and not be allowed to create new stacks.

The pickup-related items are handled in order from the player inventory (hotbar first, left to right, then the other rows top to bottom, ie. the order the slots are in), however the item types are handled in order: Item Pickup Manager, Handy Bag, Nullifier and each type finds the matching item(s) in the slot order. What I'm getting at is that it might be possible to use the order of the items to control which item handles the pickup, but since the "item type order" is hard-coded, it's not completely freely controllable. I'm not sure if I should change that, as those items are kind of meant to work in that priority order without having to worry about which order those items are in your inventory (assuming you only have one of each type, if you have more then the order within each type does matter).