HUDLayout.res
... 
The HudLayout.res file, located under a Source game's /scripts directory, defines the general look and feel of the in-game HUD. From this file, you can change among other things the location, color, font and visibility of HUD elements.
Format
Examples
- HudHealth
- Player health readout
- HudSuit
- Player armor readout
- HudAmmo
- Player primary ammunition readout
- HudAmmoSecondary
- Player secondary ammunition readout
- HudSuitPower
- Player auxiliary power readout
- HudFlashlight
- Flashlight power readout
- HudDamageIndicator
- Damage direction indicator
- HudZoom
- Dimming and large crosshair
- HudWeaponSelection
- Player weapon selection menu
- HudCrosshair
- Crosshair
- HudDeathNotice
- Notification of player deaths in multiplayer
- HudVehicle
- Vehicle crosshair
- ScorePanel
- Scoreboard
- HudTrain
- Train controls from
Half-Life: Source (exists in code but is stripped of functionality by default) 
- HudMOTD
- Message Of The Day panel
- HudMessage
- Textual display typically used by game_text and env_message entities
- HudMenu
- Better known as the "Radio Menu"
- HudCloseCaption
- Displays close captions and subtitles
- Newer games such as
Portal 2 or later have anti-aliased subtitles text (which was later appeared in 
Left 4 Dead 2, and all first-party 
Source 2013 games (except ) since 2022). 
- HudChat
- Chat text entry and display
- HudHistoryResource
- List of items/ammunition the player recently picked up
- HudGeiger
- Geiger counter (radiation indicator)
- HudQuickInfo
- Health and ammunition indicator (surrounds the crosshair)
- HudWeapon
- Handles crosshair drawing
- HudAnimationInfo
- Displays information about HUD elements, activated by the console command
cl_animationinfo 
- HudPredictionDump
- Displays information about a predicted entity's variables, activated by console variable
cl_pdump 
- HudHintDisplay
- Textual hint display
- HudHintKeyDisplay
- Display designed solely for showing localized key hints. Unlike
HudHintDisplay, this display cannot be used to display unlocalized text 
- HudSquadStatus
- Squad status indicator, shows the number and state of squad members
- HudPoisonDamageIndicator
- HudCredits
- End game credits overlay panel
- HUDAutoAim
- Console crosshair with aim assistance (magnetism)
- HudCommentary
- Display showing the duration and progress of the currently active commentary node
- HudHDRDemo
- Lost Coast HDR Demonstration HUD element
- TeamDisplay
- Player team indicator
- TargetID
- Display that shows information about the target the player is looking at
- HudVoiceSelfStatus
- Indicates to the player that their microphone is active
- HudVoiceStatus
- Indicator for the players who are currently speaking through voice chat
- HudLocator
- Display showing the location of the player's Jalopy (EP2 only)
- HudPosture
- Display whether the player is crouching or not (Console only)
- AchievementNotificationPanel
- Notification panel indicating achievement progress (usually Non-PC, except in
Black Mesa (Mod version) and unofficial Android ports by nillerusr) 
