UE4 Blogs

https://medium.com/@lordned

https://sebh.github.io/

http://casual-effects.com/

Optimization

https://unrealartoptimization.github.io/book/

http://timhobsonue4.snappages.com/tutorials.htm

UE4 Plugins & Tools

https://www.unrealengine.com/marketplace/en-US/profile/Isara+Tech.

UE4 Gameplay

EasyActions
https://www.unrealengine.com/marketplace/easyactions

Yellow Subs Machine
https://www.unrealengine.com/marketplace/en-US/yellow-subs-machine

Generic Interaction Component
https://www.unrealengine.com/marketplace/en-US/slug/generic-interaction-component

HL2-style, classic FPS movement for Unreal Engine 4 implemented in C++
https://rubygems.pkg.github.com/ProjectBorealis/PBCharacterMovement

UE4 Animation

Motion Matching System
https://www.unrealengine.com/marketplace/en-US/slug/motion-matching-system

RMAMirrorAnimation
https://www.unrealengine.com/marketplace/zh-CN/slug/rmamirroranimation

Root Motion Extractor
https://www.unrealengine.com/marketplace/en-US/slug/root-motion-extractor

Suite of tools for Autodesk Maya to help with skeleton creation, skeleton placement, rig creation, and final animation.
https://github.com/EpicGames/ARTv2

UE4 Procedural

Dungeon Architect
https://www.unrealengine.com/marketplace/dungeon-architect

Procedural Landscape Generator
https://www.unrealengine.com/marketplace/en-US/slug/procedural-landscape-generator

Procedural mesh examples for Unreal 4
https://github.com/SiggiG/ProceduralMeshDemos

UE4 Scene

WorldMachine + UE4: Full Workflow
https://80.lv/articles/worldmachine-ue4-full-workflow/

Interactive Tree Creator
https://www.unrealengine.com/marketplace/interactive-tree-creator

Dungeon Generator V2
https://www.unrealengine.com/marketplace/en-US/dungeon-generator

Ultimate River Tool
https://www.unrealengine.com/marketplace/en-US/slug/ultimate-river-tool

UE4 Materials

Landscape Auto Material
https://www.unrealengine.com/marketplace/landscape-auto-material

UE4 Landscape Auto-Material
https://gumroad.com/l/mBjSf

Environment Prop Master Materials for UE4
https://gumroad.com/l/TAiBJ

Unreal Engine 4 smear frame material effect
https://github.com/LuggLD/SmearFrame

UE4 Textures

RMATextureResizer
https://www.unrealengine.com/marketplace/en-US/slug/rmatextureresizer

UE4 Mesh

https://www.unrealengine.com/marketplace/en-US/profile/Mary+Nate

Pivot Tool
https://www.unrealengine.com/marketplace/en-US/slug/pivot-tool

Prefab Tool
https://www.unrealengine.com/marketplace/en-US/slug/prefab-tool

Instance Tool
https://www.unrealengine.com/marketplace/en-US/slug/instance-tool

Rave Spline and Mesh Builder
https://www.unrealengine.com/marketplace/zh-CN/slug/rave-spline-and-mesh-builder

Mesh Tool
https://www.unrealengine.com/marketplace/en-US/slug/mesh-tool

UE4.21 tool to automatically merge large meshes and instance smaller ones
https://github.com/alexismorin/MergeVolume

UE4 LOD

SmoothLODCreator
https://www.unrealengine.com/marketplace/en-US/slug/smoothlodcreator

BatchLodTool
https://www.unrealengine.com/marketplace/en-US/slug/batchlodtool

Procedural Mesh Simplifier (LOD Creator)
https://www.unrealengine.com/marketplace/en-US/slug/procedural-mesh-simplifier-lod-creator

UE4 Physics

PhysXPack
https://www.unrealengine.com/marketplace/en-US/slug/physxpack

UE4 Lighting

Dynamic Lighting Portal System (Performance Booster)
https://www.unrealengine.com/marketplace/dynamic-lighting-portal-system-performance-booster

Performance Optimization: Shadows Triggering Zones
https://www.unrealengine.com/marketplace/performance-optimization-shadows-triggering-zones

Cheap Ambient Lighting System
https://www.unrealengine.com/marketplace/ambient-light-probes

Dynamic Bounce Lighting
https://www.unrealengine.com/marketplace/en-US/slug/dynamic-bounce-lighting

Real Neon Sign Creator
https://www.unrealengine.com/marketplace/en-US/slug/real-neon-sign-creator

UE4 Run-time

Runtime Gizmo (Transform Tool)
https://www.unrealengine.com/marketplace/en-US/slug/runtime-gizmohttps://www.unrealengine.com/marketplace/en-US/slug/explainer-video?lang=en-US

Runtime FBX Import (Asynchronous)
https://www.unrealengine.com/marketplace/en-US/slug/runtime-fbx-import-asynchronous https://www.unrealengine.com/marketplace/en-US/slug/video-player-360-2d-180-360-stereo

UE4 Multiplayer

Steam Party
https://www.unrealengine.com/marketplace/en-US/slug/steam-beacons

UWorks
https://www.unrealengine.com/marketplace/en-US/slug/uworks

UE4 Level Design

Prefabricator
https://www.unrealengine.com/marketplace/en-US/slug/prefabricator

UE4 Water

UIWS - Unified Interactive Water System
https://www.unrealengine.com/marketplace/en-US/slug/uiws-unified-interactive-water-system

UE4 Foliage

UIPF - Unified Interactive Physical Foliage
https://www.unrealengine.com/marketplace/en-US/slug/uipf-unified-interactive-physical-foliage

UE4 Landscapes & Terrain

North Terrain Brushes
https://www.unrealengine.com/marketplace/en-US/slug/north-terrain-brushes

StitchingOfLandscapes
https://www.unrealengine.com/marketplace/en-US/slug/stitchingoflandscapes

UE4 Export

ExportObjectPlugin
https://github.com/Allar/ExportObjectPlugin

UE4 Assets Manage

Clean Project
https://www.unrealengine.com/marketplace/en-US/slug/clean-project

UE4 Building

Resource Patch
https://www.unrealengine.com/marketplace/en-US/slug/resource-patch

UE4 Lua

lua dev plugin for unreal engine 4
https://github.com/Tencent/sluaunreal

UE4 Audio

Explainer Video
https://www.unrealengine.com/marketplace/en-US/slug/explainer-video

UE4 Video

Video Player 360 (2D, 180, 360, Stereo)
https://www.unrealengine.com/marketplace/en-US/slug/video-player-360-2d-180-360-stereo

UE4 VOX Format

MagicaVoxel VOX Format import plugin for Unreal Engine 4
https://github.com/mik14a/VOX4U

UE4 Content Tools & Scripts

UE4 Pivot Painter Tool

UE4 Documents

Gamemakin UE4 Style Guide
https://github.com/Allar/ue4-style-guide

Pivot Painter Tool 2.0
https://docs.unrealengine.com/en-US/Engine/Content/Tools/PivotPainter/PivotPainter2/index.html

最高境界的处世艺术是不妥协却能适应现实，而极端不幸的个人素质是尽管不断地妥协却总是达不到适应现实的要求。——德国社会学家齐美尔（SimmelGeorg）