I tested this plugin on 1.17.1, but I think it has so simple code, it should work on all minecraft versions, if you find out that it doesn't, please PM and I'll fix it.

So why did I want to make this plugin? Well it's a simple alias for changing gamemodes and without permissions so your players doesn't have to be op or something to use this. Yeah I know it's probably now very good plugin for some survival servers, but that wasn't the thought to make this plugin. This plugin is just for you and your friends you can play some adventure map and have this plugin in place so you can get unstuck or something like that without typing out long /gamemode spectator or /gamemode creative, you just write /gmsp or /gmc. I wanted this mainly for build servers, where this server is on some kind of network and only builders have the ability to join this server, so if owner wants to have this server as few and lightweight plugins as possible he can, now he doesn't have to download large essentials and setting up permissions just for gamemode aliases to work, you just drag and drop this plugin and you are good to go.

So the commands are:
/gms - Survival
/gmc - Creative
/gma - Adventure
/gmsp - Spectator

Permissions: No!
Dependencies: No!

Just drag and drop and you are good to go

PS.: This is my first uploaded resource, so if you have any suggestions or something, I would be very pleased, if you could post any ideas in the comment section or PM me, thanks