Storage No Poof

This mod preserves the items inside block containers from removed mods, and turns the removed block into a special block which, when broken will drop all items the container used to have. Alternatively if the container had many items and you do not want to potentially cause server lag, you can extract the items out of the block until it's empty, in which case it will automatically self-destruct.

Right now only mods which stored their items in a top-level Items tag can have their data preserved (this tag is used by vanilla containers too). In the future, options for modpacks to define rules to keep items from specific tags and inventories will be added.

This mod saves the items stored in container blocks from removed mods. When such a block is missing, it is replaced with a special block that drops all of its stored items when broken. If the container held a large number of items and you want to avoid possible server lag, you can remove the items manually; once it is empty, the block destroys itself automatically.

At the moment, preservation works only for mods that store their inventory in a top-level Items tag, which is also the format used by vanilla containers. Support for custom rules, allowing modpacks to preserve items from specific tags and inventories, is planned for a future update.