South Africa's Faf du Plessis, New Zealand's Kane Williamson, England's Eoin Morgan, India's Virat Kohli, and Australia's Aaron Finch are not only good batsmen but are also good captains of the shortest format of the game. They all have been excellent with the bat as well as with their on-field tactics in T20I cricket. And here is a list of most runs, fifty-plus scores, highest averages and scores by captains in this format. 

Most Runs as captain in T20I cricket -

1273 - Faf du Plessis (South Africa, 40 Matches)

1243 - Kane Williamson (New Zealand, 42 Matches)

1149 - Eoin Morgan (England, 46 Matches)

1137 - Virat Kohli (India, 37 Matches)

1112 - MS Dhoni (India, 72 Matches)

1105 - Aaron Finch (Australia, 34 Matches)

1002 - William Porterfield (Ireland, 56 Matches)

927 - Asghar Afghan (Afghanistan, 49 Matches)

803 - Graeme Smith (South Africa, 27 Matches)

753 - Mohammed Hafeez (Pakistan, 29 Matches)

Most Fifty Plus Scores as captain in T20I cricket -

9 - Kane Williamson (New Zealand)

8 - Virat Kohli (India)

8 - Faf du Plessis (South Africa)

8 - Aaron Finch (Australia)

8 - Eoin Morgan (England)

7 - Rohit Sharma (India)

6 - Kumar Sangakkara (Sri Lanka)

5 - Kyle Coetzer (Scotland)

5 - Chris Gayle (West Indies)

5 - Brendon McCullum (New Zealand)

5 - Mohammed Hafeez (Pakistan) 

Highest Averages as captain in T20I cricket (Min 500 runs) -

43.73 - Virat Kohli (India, 1137 runs)

41.88 - Rohit Sharma (India, 712 runs)

37.44 - Faf du Plessis (South Africa, 1273 runs)

37.06 - MS Dhoni (India, 1112 runs)

36.83 - Aaron Finch (Australia, 1105 runs)

34.31 - Kumar Sangakkara (Sri Lanka, 652 runs)

32.71 - Kane Williamson (New Zealand, 1243 runs) 

32.12 - Graeme Smith (South Africa, 803 runs)

31.91 - Eoin Morgan (England, 1149 runs)

30.69 - Paras Khadka (Nepal, 706 runs)

Highest Individual Scores as captain in T20I cricket -

172 - Aaron Finch (AUS) vs ZIM at Harare, 2018

124* - Shane Watson (AUS) vs IND at Sydney, 2016

119 - Faf du Plessis (SA) vs WI at Johannesburg, 2015

118 - Rohit Sharma (IND) vs SL at Indore, 2017

111* - Rohit Sharma (IND) vs WI at Lucknow, 2018

107 - Gyanendra Malla (Nepal) vs Bhutan at Kirtipur, 2019

106* - Paras Khadka (Nepal) vs Singapore at Singapore, 2019

104* - Tillakaratne Dilshan (SL) vs AUS at Pallekele, 2011

98* - Ricky Ponting (AUS) vs NZ at Auckland, 2005

98 - Chris Gayle (WI) vs IND at Bridgetown, 2010