This plugin increases your max player limit by demand, it will increase it every X minutes, by X amount of slots, until it has reached the max limit set. All of which is configurable.

Configuration

{
  "Starting Player Slots": 75, 
  "Maximum Player Slots": 125,
  "Increment Player Slots": 2,
  "Increment Interval Minutes": 3,
  "Increment When Slots Available": 0,
  "Only increment when FPS above": 45,
  "Auto decrease again": true
}

Starting Player Slots -> This will be the max limit the server will start with.

Maximum Player Slots -> Slots will never exceed this amount

Increment Player Slots -> How many new slots should be added after every "Increment Interval Minutes"

Increment When Slots Available -> Only increment when the amount of slots available is equal to, or less than this.

Only increment when FPS above -> Will ONLY increase max slots when the FPS of the server is above this value

Auto decrease again -> Will decrease max slots again when players drop off, in reverse order of increase.