This mod is very simple yet very useful for massive storage. It essentially allows you to create several iterations of condensed blocks from 9x condensed blocks all the way to 729x condensed blocks then stacking 64 of those blocks giving you tens of thousands of blocks in a single slot. All this mod takes is for you to continually stack 9 of the same block into one block on a crafting table until you get to Maximum Condensed blocks.

This room contains 21 double chests filled with 48,384 stone blocks. I’ve taken all of those blocks, condensed them and stacked them to 11 maximum condensed blocks and 5 super condensed blocks. So 21 full double chests now only take up 2 slots of a single chest.

Safe to say your storage needs are more than covered with this mod.