Ultra Condense is a mod that lets you compact compacted blocks further, letting you store 36/81 items in just one block!
19 new "ultra condensed" blocks
These blocks are crafted using 9 already compacted blocks, like Redstone Blocks, Iron Blocks etc. !GIF demonstrating how to craft the 19 new condensed blocks added by the mod
They can be then crafted back into 9 vanilla compacted blocks.
Quartz Storage
You can now craft a Block of Quartz using 9 nether quartz, allowing it to be used as a storage block.
Beacon Support
You can use the condensed equivalents of beacon mineral blocks to power a beacon.
If you have a large amount of a material, you can now easily store it efficiently.

Lets you further compact blocks like Coal blocks and iron blocks to Condensed blocks