I found this on a website a while back, and it has been a lifesaver (pretty literally). I'm sorry I can't remember the name of the website to give the author his or her due credit.
General Names for Soy or Soy Containing Products, and Possible Sources of Soy
1. ANYTHING with Soy, Soya, Soja, or Shoyo in the name
2. ANYTHING with Lecithin (variations on spelling) in the name*
3. ANYTHING with Vegetable, Plant, or Bean in the name*
4. ANYTHING with Guar in the name*
5. ANYTHING with Xanthan or Zanthan (variations on spellings) in the name*
6. ANYTHING with Vitamin E or Toccopherol (variations on spelling) in the name*
7. MSG (Mono Sodium Glutamate)* (Please note that the terms "yeast extract/autolyzed yeast extract" refer to natural/hidden sources of MSG without having to be labeled as MSG. Though they are NOT soy, some people with MSG sensitivities also have trouble with these ingredients. For more information, see this website or Google "natural sources of MSG" or "hidden sources of MSG".)
8. Natural and Artificial Flavor or Flavorings*
9. Tofu
10. Miso
11. Tempeh
12. Edamame
13. Mono-diglyceride (variations on spelling)*
14. Natto
15. Okara or Akara
16. Yuba
17. Glycerin/glycerine/vegetable glycerin*
18. Tamari
19. Teriyaki*
20. Isolates*
21. Olean
22. Gum Arabic
23. Bulking Agent*
24. Carob
25. Emulsifier*
26. Protein or Proteins*
27. Protein Extender*
28. Stabilizer*
29. Starch*
30. Thickener*
31. TVP (Textured Vegetable Protein)*
32. HVP (Hydrolized Vegetable Protein)*
33. Alkyd Resin Solution
34. Quaternary Ammonium Salts
35. Quaternary Ammonium Compounds, Ethyldimethylsoya Alkyl, Et Soyethyldimonium Ethosulfate
36. Dimethylsoya Ammonium Ethosulfate
37. Alkyd Resin
38. Linseed Oil, Polymer with Pentaerythritol, Phthalic Anhydride, Oil, Styrene and Vinyltoluene
39. Soyaethyl Morpholinium Ethosulfate
40. Morpholinium Compounds
41. Ethyl Sulfates
42. Soyatrimonium Chloride
43. Quaternary Ammonium Compounds
44. Trimethylsoya
45. Alkyl Chlorides
46. Quaternium-9
47. PEG 5 (soy sterol)
48. PEG 10 (soy sterol)
49. PEG 16 (soy sterol)
50. PEG 25 (soy sterol)
51. PEG 30 (soy sterol)
52. PEG 40 (soy sterol)
53. Stearic acid/vegetable stearic acid or ANYTHING with stearic in the name*
54. Magnesium stearate*
55. Tyramine* (This is a naturally occuring amino acid in many foods, including soy.)
56. Abura-age (sliced deep-fried tofu)
57. Atsu-age (deep-fried tofu)
58. Gan-modoki (a soy dumpling)
59. Glycine max
60. Kinako (Japanese for soybean flour)
61. Kyodofu (freeze-dried bean curd)*
62. Nimame (stewed soybeans)
63. Shoyu
64. Uno-hana (soy pulp)
65. Hydrolyzed plant protein (HPP)*
66. Isolated vegetable protein*
67. Methylcellulose*
68. Monoglycerides*
69. Protein filler*
70. Caprylic Triglyceride
71. Monotriglyceride
72. Ascobyl Palmitate
73. Isostearyl Isosterate
74. Glycols
75. Tocotretrienols
*Note: Not always do these (*)ed products contain soy. However, unless they are labeled specifically that they do not contain soy or a soy containing product, or you can contact the manufacturer directly and they tell you the product does not contain soy or a soy containing product, ASSUME that it does contain soy or a soy containing product.