GardenStone in his Gods of the Germanic Peoples. From Roman times to the Viking Age Volume 1 refers to a Goddess Isenbucaega/Isenburcaga (page 309). A votive stone from 222CE in the Dutch village of Zennewijnen near Tiel is dedicated to the Goddess:
"DEAE ISENBUCAEGA ILPIUS FILINUS PP TRIBUNUS LEGINAE X U V SEVERIANE ALEXANDRIANE ARAM CUM EDE SUE A SE REFECIT VOTUM LIBENS SOLVIT MERITO IMPERIO D N SEVERO ALEXANDRO AUGUSTO CONSULIBUS"
Ulpius Filinus was a military tribune of the 30th legion and he dedicated this altar on behalf of the mother of the emperor Severus Alexander. Why it should be dedicated to a Germanic Goddess rather than a Roman one is anyone's guess. GardenStone interprets (correctly in my opinion) that Isenbucaega is connected with the Germanic *isarna and *isana, meaning 'iron'. He points out that sand found in this area is red-coloured and this may be the result of oxidated iron.
GardenStone also speculates that blacksmiths may have forged weapons in the area and thus "the goddess would have been their protectress." If this is the case then as GardenStone argues the second part of the name bucaega would be Gaulish and a place name. This would make the Goddess a Gallo-Germanic deity and as GardenStone reasons She "must have been of some importance" for a high-ranking Roman officer to dedicate this altar to Her.
He offers another interpretation of the name, suggesting that the second part of the name could relate to the Germanic *buga, meaning vault. This he speculates could mean a vault where iron or weaponry is stored. Either way this is clearly a deity who presides over the sacred metal iron.
In Teutonic Mythology Volume 1 Jacob Grimm in discussing the Goddess Isis referred to in Tacitus' Germania states:
"We must not omit to mention, that Aventin, after transforming the Tacitean Isis into a frau Eisen, and making iron (eisen) take its name from her, expands the account of her worship, and in addition to the little ship, states further, that on the death of her father (Hercules) she travelled through all countries, came to the German king Schwab, and staid for a time with him; that she taught him the forging of iron, the sowing of seed, reaping, grinding, kneading and baking, the cultivation of flax and hemp, spinning, weaving and needle work, and that the people esteemed her a holy woman." (My emphasis).