Game UI Frameworks

In-game UI: HUDs, menus, inventory grids, dialog boxes. Pairs with 3D engines, 2D engines, animation for tween libs that some web-tech-in-game frameworks pull in, and localization. For full landscape see Game Development.

The interesting trend: web tech is creeping into game UI. NoesisGUI (XAML, but Web-y), Coherent Gameface (HTML/CSS), Ultralight (HTML/CSS) all let you author menus in browser-flavored tools and ship them in-engine. Whether this is the future or a niche depends on which game you ask.

Engine-built (default for most)

★ Unity UI Toolkit + UGUI — Unity ships two: UI Toolkit (newer, USS/UXML, runtime + editor) and UGUI (older, Canvas-based, still dominant). UGUI has more tutorials; UI Toolkit is the future.
★ Unreal UMG + Slate — UMG is the Blueprint-able front-end, Slate is the C++ underlying widget framework.
★ Godot Control nodes — built in, very capable, mostly delightful in Godot 4.

Web-tech in games

NoesisGUI — paid (~$0–$2,500 depending on revenue tier), XAML-based. Used by Hearthstone, Robocraft. Wide engine integrations.
Coherent Gameface — paid, HTML/CSS/JS in Unity/Unreal. Used by Halo Infinite menus.
Ultralight — paid for commercial above thresholds, free for indie. HTML/CSS/JS embedded WebKit-derived renderer; lighter than CEF.
Berserk — paid, alt HTML-in-game.
CEF (Chromium Embedded Framework) — free, heavy, but real Chromium. Used in some games for browser-based UI/streams.

ImGui-style (debug / tools UI)

★ Dear ImGui — free OSS, the developer-tools UI standard. Excellent for level editors, debug overlays, dev consoles. Not really for game UIs but ubiquitous in tools.
Nuklear — free OSS, single-header C immediate-mode UI.
egui — free OSS, Rust immediate-mode UI; pairs well with Bevy.
iced — free OSS Rust retained UI; less common in games.

Godot themes, Unity UI Toolkit themes — engine-native.
Game UI Database (free, just inspiration) — searchable game UI references.

In-game web view (full browser)

CEF, Ultralight, WebView2 — free or with commercial tiers; embed real web pages.

VR / XR UI

Unity XR Interaction Toolkit — built in.
Unreal VR Template / XRUI — built in.
Three.js / A-Frame for WebXR — see 3D / WebGL.

Inputs that drive UI

See input systems for controller, keyboard, touch and rebinding.

Localization

See game localization.

Pricing summary

Free / built-in: Unity UGUI / UI Toolkit, Unreal UMG / Slate, Godot Control, Dear ImGui, Nuklear, egui.
Paid revenue-tiered: NoesisGUI, Coherent Gameface, Ultralight (commercial), Berserk.
Free heavyweight: CEF.

Pick this if…

Default in your engine: built-in.
Web designer authoring UIs: Coherent Gameface or Ultralight.
Wide engine reach + designer toolchain (XAML): NoesisGUI.
Dev tools / level editor UI: Dear ImGui.
Bevy: egui.
VR / XR: XR Interaction Toolkit (Unity) or VR Template (Unreal).