Two hat-tricks in one innings

Bowler
J.S.Rao* Services v N.Punjab Amritsar 1963-64
A.E.Trott* Middlesex v Somerset Lord's 1907
*JS Rao: three hat-tricks in 2 consecutive matches - also took hat-trick in his debut innings
*AE Trott:4 wickets in 4 balls in the first instance

Two hat-tricks in one match

Bowler
R.O.Jenkins Worcestershire v Surrey Worcester 1949
Amin Lakhani Combined XI v Indians Multan 1978-79
T.J.Matthews Australia v S.Africa Manchester 1912
C.W.L.Parker Gloucestershire v Middlesex Bristol 1924
J.S.Rao Services v N.Punjab Amritsar 1963-64
A.Shaw Notts v Gloucs Nottingham 1884
A.E.Trott Middlesex v Somerset Lord's 1907