Tibera.org - Was my favourite server, tons of player conflicts, tons of war, several different guilds coming back after every reset such as Essentials, Apple, Dedka. Always dies out after 2-3 months because the owner, Richux rarely updated the server and people got incredibly bored with the same map and quests, but kept coming back after every reset to claim the server. People like Acr Cronik and Smakapara were the people that made this server to what it was, despite our differences.
The first Noobwar server - Hosted by one of the old Swedes from this forum, this server went from 0 to 300 players the first day. You started at level 8 and it took a day for the first person to reach level 11. You lost EXP when you died, but not all of it. Tons of teams with 10-20 people were formed and people had a great time. You could also get addons when you killed a BUNCH of people, and later on the owner added a quest. The server died when the owner tried to create a mainland for higher levels, aswell as he started banning people for incredibly childish reasons.
Pokémononline.com.br - This was the first pokémon server and it had a HUGE succes. Over 1000 players online on every world and it had a waiting que for hours. This was also the biggest thread ever created here on OTLand and it eventually got it's own subforum. The server lasted for quite some time until it got shut down, rumors are that they got sued by CipSoft but I don't know anyone that could confirm this. PAdventures was still in development when pokémononline got shut down but eventually got released. Aswell as pokémononline this was a huge success, but it has lost a lot of it's players over the years.
That one PL custommap - I don't remember the name on this server, but it was mainly Polish players. This is where I met my first team during Tibia and I played with them across many servers. They are known as "the Dawg team" and they also played RL Tibia. The map though was amazing, it was big and had several continents. No bugs and the XP-rate was okay. The server had over 500 players in it's prime and I was one of the members of the ruling guild, which happend to be an English speaking one (1% of the server pop). EDIT: This map was sold because the server shut down and was hosted on MULTIPLE other servers, but never reached anywhere near the success of this server.