I have yet to find a game that has a similar system to Fiesta Online’s Kingdom Quest.
KQs were special dungeons/map/quest (whatever u want to call it), basically an instance map, that would open at specific times during the day, limited by level, amount of players that could get in, and time to complete it. For each kind players would have to do this or that strategy. The rewards most of the times were mats, sometimes rare weapons.
What I personally love about KQs is that you get to know players better. Since it’s scheduled and requires everyone to cooperate, you would see familar faces and know how they play. It was a good way to make friends in game.
Unlike other instance dungeons where you log in whenever, party with randoms, do your grind and forget about them the next day.