Well, to summarize it we can consider the Ironman Mode as a self imposed restriction on the gameplay of the game in order to make it more difficult and challenging. The goal is to follow it as a personal challenge, and it is worth mentioning that Tibia can be also considered as a sandbox MMORPG so you can pretty much do anything that you want, just like some people like to do role play adventures on it with a group of people.
The core of Ironman is to impose heavy restrictions on player to player interactions meaning that market or using the Advertise tab is prohibited. The character improvement would be closed only to NPCs interactions, quests and slaying mobs.
Here are some general guidelines that a guild specialized on this mode made for it. I got the most common ones that you should expect when venturing as Tibian Ironman:
- You cannot use Tibia Coins to acquire items, pick items scattered on the ground, perform player-to-player trading or loot random corpses that doesn't belong to you. If you can't obtain an item by yourself purely, you should not have it.
- No XP vouchers.
- No blessings until level 100 (death penalty is viewed as a welcome restriction here on this mode. You should really feel the impact of deaths).
I've obtained the information above from https://www.reddit.com/r/TibiaMMO/comments/4wxl0n/official_ironman_discussion/
Additionally, keep in mind that there can be controversies on how it is the most "effective" or realistic Ironman Mode available. On another topic, I also could see a player self imposing the restriction of doing quests as well and also states that you should begin with zero equipment and restricts the acquirement of gear from NPCs (except potions or runes, that need to be bought on stores), which makes you by your own literally without any armor or weapon until you loot one from something. Curiously, the player also made his adventure viable only through Free Account lands as well, mainly for nostalgic reasons and because the Premium lands are usually much more lucrative to hunt.
If you are interested about the fate of the guild that used to play this way, they are currently disbanded unfortunately (but they had at least 100 members at the peak). You can read a little bit more about their history here. The guild even managed to have videos of team hunts that they completed together!
You can however try to find more gamers that still adopt this gameplay alone or with groups. I recommend doing it by consulting Tibia official forums or other large internet places where the fan base usually gather around (like Reddit). I like to see players enjoying other forms to play this game! It seems fun and very challenging, and you can do it even as a Free Account!