Hi aternos team
CommandPanel is a plugin of creating custom guis . The plugin have 2 versions 1 for 1.13 and higher and other Called Command Panel Classic for 1.12 and lower .
Name : commandPanel classic
versions: 1.8 - 1.12
Spigot link :
https://www.spigotmc.org/resou…lassic-custom-guis.77182/
Thank you aternos team 
for every thing