MSG is misunderstood, you have to be carefull that other seasonings/sauces/condiments don't already have added MSG as many do.
You also have to remove regular salt proportionally- again if your other seasonings already have salt this can be challenging.
Many spirits used for de-glazing aren't well known because dumb white chefs just list substitutes.
Rice wine four southeast asian, China as xiouching rice wine, rose wine and also baiju which can be hard to get because it's 60% ABV and that's a problem in a lot of western countries- none can really be substituted with wine.
China also has "red oil" which is really a foundational seasoning in Chinese cuisine.
Fermented soybeans are used widely in easy Asian cooking and help reduce salt, especially in soups.
Lotus roots are GOAT as somehow they freeze well and remain crunchy even after prolonged boiling- similar to water chestnuts.
Pickled greens like ya cai and kimchi are also foundational because they add acid
Black garlic has a reputation as a meme but actually is easy to make
Smoked salts are very hard to make well and overpriced to purchase.
Game animals are often forgotten about because they don't freeze well and aren't farmed
Vegan rennet is great because it's cheap and lasts longer than sheep rennet, it's great for making cottage cheese and green pies/casseroles or even for making fresh cheeses for salads/pizza
From india Ghee is used extensively, stores easily and is used mainly as a cooking fat
Paneer is also great but underutilized in non indian dishes
Strangely enough white people don't get green chilies
Cardomon is something white people also don't get because they typically fail to appreciate gow strong it is, in the same way the first time they use sichuan peppercorns they add way too many
Happy to help with specific cuisines if I can