For those of you, like me, who are into 3D printing, here is a quick, and VERY helpful set of marlin gcodes for your Marlin firmware. It will help you when you have to diagnose the errors on-screen, and it will help you even more, if you use the command sets through octoprint. Now onto the latest GCode as of Marlin 2.0.5
G0-G1: Linear Move
G2-G3: Arc or Circle Move
G4: Dwell
G5: Cubic spline
G10: Retract
G11: Recover
G12: Clean the Nozzle
G17-G18: CNC Workspace Planes
G20: Inch Units
G21: Millimeter Units
G26: Mesh Validation Pattern
G27: Park toolhead
G28: Auto Home
G29: Bed Leveling
G29: Bed Leveling (3-Point)
G29: Bed Leveling (Linear)
G29: Bed Leveling (Manual)
G29: Bed Leveling (Bilinear)
G29: Bed Leveling (Unified)
G30: Single Z-Probe
G31: Dock Sled
G32: Undock Sled
G33: Delta Auto Calibration
G34: Z Steppers Auto-Alignment
G38.2-G38.3: Probe target
G42: Move to mesh coordinate
G53: Move in Machine Coordinates
G54-G55: Workspace Coordinate System
G60: Save Current Position
G61: Return to Saved Position
G76: Probe temperature calibration
G80: Cancel Current Motion Mode
G90: Absolute Positioning
G91: Relative Positioning
G92: Set Position
G425: Backlash Calibration
M0-M1: Unconditional stop
M3: Spindle CW / Laser On
M4: Spindle CCW / Laser On
M5: Spindle / Laser Off
M16: Expected Printer Check
M17: Enable Steppers
M18-M84: Disable steppers
M20: List SD Card
M21: Init SD card
M22: Release SD card
M23: Select SD file
M24: Start or Resume SD print
M25: Pause SD print
M26: Set SD position
M27: Report SD print status
M28: Start SD write
M29: Stop SD write
M30: Delete SD file
M31: Print time
M32: Select and Start
M33: Get Long Path
M34: SDCard Sorting
M42: Set Pin State
M43: Debug Pins
M43 T: Toggle Pins
M48: Probe Accuracy Test
M7-M8: Coolant Controls
M73: Set Print Progress
M75: Start Print Job Timer
M76: Pause Print Job
M77: Stop Print Job Timer
M78: Print Job Stats
M80: Power On
M81: Power Off
M82: E Absolute
M83: E Relative
M85: Inactivity Shutdown
M92: Set Axis Steps-per-unit
M100: Free Memory
M104: Set Hotend Temperature
M105: Report Temperatures
M106: Set Fan Speed
M107: Fan Off
M108: Break and Continue
M109: Wait for Hotend Temperature
M110: Set Line Number
M111: Debug Level
M112: Emergency Stop
M113: Host Keepalive
M114: Get Current Position
M115: Firmware Info
M117: Set LCD Message
M118: Serial print
M119: Endstop States
M120: Enable Endstops
M121: Disable Endstops
M122: TMC Debugging
M125: Park Head
M126: Baricuda 1 Open
M127: Baricuda 1 Close
M128: Baricuda 2 Open
M129: Baricuda 2 Close
M140: Set Bed Temperature
M141: Set Chamber Temperature
M145: Set Material Preset
M149: Set Temperature Units
M150: Set RGB(W) Color
M155: Temperature Auto-Report
M163: Set Mix Factor
M164: Save Mix
M165: Set Mix
M166: Gradient Mix
M190: Wait for Bed Temperature
M191: Wait for Chamber Temperature
M200: Set Filament Diameter
M201: Set Print Max Acceleration
M203: Set Max Feedrate
M204: Set Starting Acceleration
M205: Set Advanced Settings
M206: Set Home Offsets
M207: Set Firmware Retraction
M208: Firmware Recover
M209: Set Auto Retract
M211: Software Endstops
M217: Filament swap parameters
M218: Set Hotend Offset
M220: Set Feedrate Percentage
M221: Set Flow Percentage
M226: Wait for Pin State
M240: Trigger Camera
M250: LCD Contrast
M260: I2C Send
M261: I2C Request
M280: Servo Position
M281: Edit Servo Angles
M290: Babystep
M300: Play Tone
M301: Set Hotend PID
M302: Cold Extrude
M303: PID autotune
M304: Set Bed PID
M350: Set micro-stepping
M351: Set Microstep Pins
M355: Case Light Control
M360: SCARA Theta A
M361: SCARA Theta-B
M362: SCARA Psi-A
M363: SCARA Psi-B
M364: SCARA Psi-C
M380: Activate Solenoid
M381: Deactivate Solenoids
M400: Finish Moves
M401: Deploy Probe
M402: Stow Probe
M403: MMU2 Filament Type
M404: Set Filament Diameter
M405: Filament Width Sensor On
M406: Filament Width Sensor Off
M407: Filament Width
M410: Quickstop
M412: Filament Runout
M413: Power-loss Recovery
M420: Bed Leveling State
M421: Set Mesh Value
M422: Set Z Motor XY
M425: Backlash compensation
M428: Home Offsets Here
M486: Cancel Objects
M500: Save Settings
M501: Restore Settings
M502: Factory Reset
M503: Report Settings
M504: Validate EEPROM contents
M524: Abort SD print
M540: Endstops Abort SD
M569: Set TMC stepping mode
M575: Serial baud rate
M600: Filament Change
M603: Configure Filament Change
M605: Dual Nozzle Mode
M665: Delta Configuration
M665: SCARA Configuration
M666: Set Delta endstop adjustments
M666: Set dual endstop offsets
M701: Load filament
M702: Unload filament
M710: Controller Fan settings
M851: XYZ Probe Offset
M852: Bed Skew Compensation
M871: Probe temperature config
M900: Linear Advance Factor
M906: TMC Motor Current
M907: Set Motor Current
M908: Set Trimpot Pins
M909: DAC Print Values
M910: Commit DAC to EEPROM
M911: TMC OT Pre-Warn Condition
M912: Clear TMC OT Pre-Warn
M913: Set Hybrid Threshold Speed
M914: TMC Bump Sensitivity
M915: TMC Z axis calibration
M928: Start SD Logging
M997: Firmware update
M999: STOP Restart
M7219: MAX7219 Control
T0-T1: Select Tool