The Rune table is used as an upgrade for the Galdr table. It is one of the two upgrades currently available to the Galdr table, along with Unfading candles. Its building materials can be taken through a portal.
Also, unlike the other craft station upgrades which can be placed anywhere and provides buffs within range, this upgrade building's placement is only valid connected to the Galdr table.
Rune table amplifying Galdr table on the right