Here is the list of Auto first downs on the defense
according to this.
AUTOMATIC FIRST DOWNS (DEFENSIVE FOULS)
Pass interference
Striking; tripping
Targeting/Initiating Contact w/Crown of Helmet
Contact to head/neck area of a defenseless player
Clipping
Blocking below the waist
Late Hit/action out of bounds
Helmet / Face Mask Fouls
Roughing the passer
Chop Blocking
Leverage/Leaping
Fouling an opponent obviously out of the play
Hurdling
Illegal contact against the snapper
Horse Collar Tackle
Roughing the kicker
Unsportsmanlike Conduct
Illegal contact with eligible receiver
Fighting [also disqualification]