1. fairly -
uncommonly - rather - quite
the other three are synonyms
2. obviously - noticeably - clearly - usually
the other three are (more or less) synonyms
3. commonly - usually - quietly - normally
the other three say something about how often something happens (indefinite adverbs of frequency)
4. slowly - rapidly - quickly - fast
‘slowly’ is the opposite of the other three words
5. motivating - stimulating - encouraging- uninspiring
‘uninspiring’ is the opposite of the other three words