They're on the sidebar on the subreddit but, if you want them here too, here they are!

Official TerraReddit Servers:
Server #1 (Jgallant)
Server Address: t.jgallant.com (7777)
Server Rules and More Information
Max Slots: 15~20

Server #2 (OptimusPrizzle)
Server Address: ter.optimusprizzle.com (7777)
Server Rules and More Information
Max Slots: 20

Server #3 (PnKllr.net)
Server Address: terraria.pnkllr.net (7777)
Server Rules and More Information
Max Slots: 10