Tamarind paste
Guess this is not considered a sattvic spice – it is very sour. I use very few of it and not every day. The only effect I felt so far was that it hurts on the teeth, if consumed to often or raw, because of its sourness.
I like to use Tamarind for baking (in combination with bicarbonate) or instead of soy sauce.

Tamarind is the only sour food I tolerate so far (be aware, it is from the legumes family). Lemon, lime, vinegar etcetera give me symptoms. I can’t even smell vinegar without starting to feel histamine levels rising.
I find it nice to sometimes have a taste of sour in the kitchen.