Difficult to narrow it down to just three with a mix of genres.
GTA V is a very good game, the main game is a decent length and there's plenty of online content.
World of Warcraft you can always try as I believe it's got a free to play element nowadays, not a huge fan myself as I prefer a bit more of a team focus when it comes to MMO games.
Strategy - Depending on what era you prefer, Crusader King/Europa Universalis/Hearts of Iron (Paradox Interactive's grand strategy titles can be insanely addictive). Europa Universalis IV is one of my all-time favourite games.
Building - Planet Coaster & Cities: Skylines are both excellent with a lot of out of the box content with added mod support.
Roleplay - Witcher 3 and Divinity: Original Sin will give you the best of the two major styles.
Another game that can be somewhat time consuming but can easily be played in short sessions is The Binding of Isaac, it's fairly simple in graphics but in terms of gameplay it gets very complex the more times you play it as there's hundreds of unlocks that randomise the action.