Cross-reactions are those that are caused by similar chemicals in other products - they are not soy in origin.
Soybean is a member of the Fabaceae or Leguminosae - the legume, pea, or bean family.
It's usually the protein that causes the problems. As proteins are chains of polypeptides containing strings or sequences of amino acids, plants from the same family tend to have polypeptides and/or amino acids in common. Thus the protein from one plant in the family can be similar enough to cause a reaction that soy would normally cause ...
Peanuts, Liquorice/liquorice, Lupins, Chickpeas
Tamarind, Tamarindus indica, is a unique species of legume tree.
Guar gum comes from seed pods of Guar which is a legume.
Gum arabic is from the sap of two species of the acacia tree, which are legumes.
Gum Tragacanth is from the sap of several species of trees, that are legumes
"vegetable" gums could mean anything ..
Runner bean, Lima bean, butter bean,black bean, kidney bean, pinto bean, green bean, navy bean, kidney bean, mung beans etc
Cassia or senna is a member of the bean family. This cassia does not refer to not Cinnamomum aromaticum or cassia cinnamon that is used in baking ..
Black-eyed/garden/Snap/Snow pea, Yellow/white/red pea, green/red lentils
Carob, Alfalfa, Kudzu
Fenugreek, Trigonella foenum-graecum, is a member of the pea family while Fennel, Foeniculum vulgare, is a perennial herb and not related.