Here are my indispensable condiments and/or sauces:

• 腐乳 (fǔrǔ, or "fermented bean curd"). If you've been in a Chinese grocery and saw the red or yellow cubes in a suspicious-looking slightly translucent liquid, that's the stuff. I use it in congee. I use it on steamed buns like butter (spread very thin). I toss a cube into a stir-fry to give it an instant lightly-sour, heavy-umami boost. It works well to jazz up slightly under-developed noodle soups too if you screwed up the broth and found out too late.
• 豆豉酱 (dòu chǐ jiàng, or "fermented black bean sauce"). This is most popularly (for a good reason!) the 老干妈风味豆豉辣椒酱 (Lǎo Gānmā fēngwèi dòuchǐ làjiāo jiàng, or "Lao Ganma fermented black bean chili sauce). Lao Ganma (literally "old dry mother" but more accurately "old godmother") is a China-wide brand that has absolutely nailed this sauce. The only time I've had it better was made from scratch by a withered lady from Guizhou. The various sauce-alikes in grocery stores are inferior copies.
• 剁辣椒 (duò là jiāo, or "[Hunan] chopped peppers"). This is a Hunan export that uses chilies grown in Hunan's terroir that then ... well ... as the name suggests, get chopped. They're then salted/pickled. It sounds simple, because it is, but that simple process results in the weirdest ambrosia I've tasted in my life. You want to liven up purple taro? Throw in a spoon or ten of this and what was once a pleasant, but a bit drab, staple turns into a lively, tasty thing that people look forward to eating. It can also be used, like the furu above, to spice up a drab stir-fry like bok choi or other leafy greens. It is used as a marinade for roasted chickens. And when I make OTHER pickles (like pickled string beans) a spoonful of this mixed in gives it a really nice sparkle.