The trio follow Mark Regan and Roy Winters, who have also recently pledged their futures to the club.
Clarke, who has overcome shoulder surgery to win a regular place in the side this season, has signed for a further three years.
Crompton, who is in his second spell at Bristol, has agreed a one-year extension to the end of next season while Taumalolo will stay for a further two years. Taumalolo joined the club from Neath this year.
Head coach Richard Hill said: "I'm absolutely delighted and it's a real statement of our intent to become a force in English and ultimately European rugby for some time to come."