Ollieminecraft
the original and some would say the best. A purpur based vanilla+ server with a couple of interconnected SMP worlds. In near-constant production for over a decade, this server has more history than most American nations.
Available at www.olliemon.co.uk:25565
OllieModcraft
The second server, a neoforge based SMP world. Much more recent, and with much more tomfoolery. Modpacks are probably going to be available to download at some point, I guess.
Available at www.olliemon.co.uk:25566
Enshrouded
A 2024 survival crafting game with stunning visuals and a unique building mechanic. Hosted as a Steam compatible server.
S.C.U.M
A massive open world survival horror/crafting/shooter game. Like DayZ but way less sweaty, better crafting elements - you name it. Private server is currently pending when the Devs release the server binaries.