Combat first: duels, arenas, kits and a ladder worth climbing.
One of the larger Spanish-language networks, with skywars, capture the flag, skyblock and creative plots. Java, 1.8 upward.
mc.universocraft.com
A dedicated PvP practice server for North America: duels, kits and ranked ladders rather than a world to build in. Java only.
na.minemen.club
Survival and prison with mcMMO skill progression and rank unlocks that cost nothing, plus skyblock and PvP. Java and Bedrock.
play.wildnetwork.net