Adding more:
Plugman - Sponge’s /sponge plugins and subcommands are adequate for the ‘listing’ part, and as for the ‘reloading’ part, Sponge plugins cannot be dynamically loaded or unloaded, as they hook into core registration which can only be in the initialization. There’s an opt-in system for reloading plugins, though, whose behavior is defined by the plugin and which is triggered via /sponge plugins reload.
ProjectKorra is very much a subcommunity plugin, designed for roleplaying in one specific universe, so no equivalent has been made yet. You’re welcome to form a plugin request but if you do, try to write out specific features instead of just saying ‘make a clone of this plugin’.
floAuction - There’s Hassan’s ItemAuction, but it doesn’t go past 1.10.2.
ClearLagg - In fact one was moved to Ore not four hours ago.
CraftBook supports Sponge as well, you just need to download the Sponge version from EngineHub.
And however much EssentialsX is still being updated is not relevant to its functionality here. This is a completely different API with different structure, semantics, features, and use. One can port an idea, but it is much harder to directly port the code.