Currently, the most popular method of advertising player-made events is the World board of the world where the event is taking place. Players will usually also use the Advertising, English chat or World chat to advertise the event directly in the game.
Other than that, there's a fansite dedicated to events - Tibia Events that contains a section with event announcements.
Finally, some players will also go to the Gameplay board to advertise the event.
Christmas Lottery eventPosted on Wednesday November 21, 2018
Full list of badges?Posted on Saturday November 24, 2018
Downvotes have been streghtened todayPosted on Saturday November 24, 2018