1. Viv Richards
He could have been immensely successful in T20s. Even in the ODIs, his career strike-rate exceeded 90 when the norm was 50 or 60. Flatter wickets, meatier bats, shorter boundaries, rules oriented ever more in favour of batsmen and less menacing bowlers in current era would have doubled his impact.
2. Brian Lara
The T20s became a popular brand towards the fag end of his career. He dabbled in the format in the now defunct ICL and tried to enter the IPL through the auction but there was no takers for the Trinidadian left-hander. But we can safely assume that if the shortest format came into existence, Lara would have mastered it because he had a tremendous footwork and wide array of shots.
3. Carl Hooper
The Guyanese all-rounder could have been an instant hit in T20s. On his day, he could destroy any bowler with a dazzling array of shots and was comfortable taking aerial route too. Hooper was a handy off-spinner and a very good fielder as well. His strike-rate in ODIs was a healthy 76 and took 193 wickets at a good economy of 4.3.
4. Joel Garner
The ‘Big Bird' could have been a priceless addition to T20s. He was miser than Shylock in giving away the runs and had a lethal toe-crushing yorker. At 6'8 he could generate disconcerting bounce and pace off the wicket too. In 98 ODIs, he grabbed 146 wickets at an astounding average of 18.84 and economy was 3.09. In this era, batsmen would have had a tough time getting him away.
5. Curtly Ambrose
Ambrose never played a T20. But his ODI stats - 225 wickets from 176 matches at an economy rate of 3.45 and an awesome strike rate of 41 - tell us that the Antiguan fast bowler could have been lethal in the shortest format too. Apart from pace, Amby had enough variations to keep the batsmen under check.