Here you can find the leaderboard for the Zelda Trilogy speedruns as well as resources to help you learn to speedrun these games.
If you want information about speedrunning The Legend of Zelda or Zelda II: The Adventure of Link, check out Red Candle.
If you want to learn about speedrunning A Link to the Past, check out the wiki.
If you want to talk with people about the games in the trilogy, check out the individual discords. There is also a discord dedicated to the trilogy as a whole.