I did look this up online but many of those topics are years old, and could be outdated, for all I know.
I also wanted to hear from other players regarding their personal experiences in this matter.
Where do you recommend trying to get a gold key from?
I started Darkmoor (which has special gold key treasure rooms), and then realized I had no gold key. I thought I had. Maybe I spent it in the past? I don't remember. I had none in my banks either.
Which instance or boss or battle did you find easiest or most fun and also dropped a gold key with steady frequency? Or is there such a thing?
Well, I know for a fact that the Winterland Pack has a very rare chance of dropping it. It's the pack that's only available during the Christmas season by the way. I got one last season from the pack, still have it to this day o:
As for other sources, stronger bosses such as Omen, Rattlebones (Both Rank 7 and 14) share chances of dropping the item but as you know, it may take some time to actually receive it.
As you were wondering, "Graveyard" is the 3rd dungeon in the Darkmoor side-world. You must have beaten the quest Walpurgisnacht in the upper halls of Darkmoor. If you have know idea what i'm talking about then you're probably not level 100+, if you are, go visit Dworgyn in Nightside to get the quest Branches of Woe to start your journey! As For Omen Stribog and Rattlebones: Rattlebones: Exalted Rattlebones is a COMPLETELY option boss, that you can fight in the "One-Shot Battle" dungeon (purchased through the crown shop) named "Exalted Rattlebones" you can also get these from a variety of bosses: Omen, Rattlebones, Exalted Rattlebones etc. Omen Stribog Omen is one of the most troublesome bosses in the game at this point, having a sentinel that intercepts 25% damage with 99,999 health. But Omen is only accessed through a gold key, so I would stay away from him for now. (He is also only intended to be for levels 110+)
So, one of the gold key drops requires a gold key and the other of 3 possible gold key drop bosses is in the dungeon where one should have a gold key before one enters.
Hmm, how very meta.
After I posted I saw a Rattlebones on my property and thought that might be the same one, but wasn't sure.
I finished two parts of Darkmoor and decided to leave and wait until I had a gold key since it wouldn't do me any good otherwise. I hadn't known the good gear is in the gold key treasure rooms.
I'm max but I don't always do the side dungeons or key rooms.