A. Mitigators are the opposite of intensifiers. When we want to make an adjective less strong we use these words: fairly, rather, quite
A1. and in informal English: pretty.
A2. But quite: when we use quite with a strong adjective it means the same as absolutely.
B. Mitigators with comparatives: a bit; just a bit; a little; a little bit; just a little bit; rather; slightly
B1. We use slightly and rather as mitigators with comparative adjectives in front of a noun.