Sponge does not work with Bukkit plugins. Here’s some recommendations
WorldBorder alternative - Releases · trentech/ProjectBorders · GitHub
Essentials alternatives - Nucleus: The Ultimate Essentials Plugin (MC 1.10.2, 1.11.2, 1.12.2) and ⚛ Nexus v1.8.5b - Providing 100+ Essential Commands and Features
Others - https://forums.spongepowered.org/c/plugins/plugin-releases