The source for creating a new bot with just one purpose "to get all discord member names". If you are intested feel free to take it.
Bot Fuction ?getguildmemberlist bot will reply with displaynames of user in the server e.g. name1,name2 including bot name
You have to give bot permission "guild" as well inorder to use it. To create a discord bot look for the tutorial in the internet there's plenty of it.