The servers are still runnig 1.16, and require 1.16 plugins, though you can use something like ViaVersion and ViaBackwards to support players joining with all the way back to 1.8.
None of the links you provided are good since they all come from non-reputable sites. These plugins may contain viruses or other malware. Please only use BukkitDev, SpigotMC, Github, etc.