Rio 2016 Medals Table
The two medalists with the largest number of gold medals from the Olympic games in Rio 2016 as of now are Michael Phelps and Katie Ledecky - both swimmers from the United States team.
You can see the full list in this visualization, but you can also easily adapt it to see the top medalists of single other Olympic games. Just go to "options" and choose the games you are interested in!