a bit vs only too

a bit

adv
  • Very. 

  • Slightly; rather. 

  • To a small extent; in a small amount. 

  • A lot. 

only too

adv
  • very, all too. 

  • to a high degree; very well or very much 

How often have the words a bit and only too occurred in a corpus of books? (source: Google Ngram Viewer )