One of the widely used Discord API endpoints is "GET /users/@me." This endpoint retrieves the user object for the account making the request, providing information such as the user's username, avatar, and whether the user is a bot. Another significant Discord API endpoint is "POST /channels/{channel.id}/messages." This endpoint is utilized to send a message to a specific channel, with the channel ID being placed in the designated placeholder. Finally, there is the "GET /guilds/{guild.id}/members" endpoint. This endpoint enables a bot to obtain a list of all members in a guild or server by including the guild ID in the placeholder in the endpoint URL.