7 tools whose vendors document an official Blender plugin, integration or export target, in alphabetical order (this isn't a ranking). Most other tools export standard files (PNG, FBX, GLB, WAV and so on) that work in any engine: see all tools. Check each tool's commercial-use notes before you ship.

Rigging, animation & mocap · Free tier + paid →
Physics-based keyframe animation software with AI-assisted autoposing, inbetweening and mocap cleanup; exports FBX, DAE, USD and glTF on paid plans.
For hand-keyed character animation with AI posing help; free is non-commercial, and Indie only covers studios under $100k a year in revenue/funding.

Rigging, animation & mocap · Free tier + paid →
Markerless AI motion capture: turns ordinary video into 3D character animation; sister product SayMotion does text-to-motion.
For turning reference video into 3D animation cheaply; the free Freemium tier is non-commercial only.

3D model generation · Free tier + paid →
Rodin generates 3D models from text or images, with options like high-poly quad meshes; the platform also lists HDRI and texture generators.
For high-detail 3D generation; commercial rights on the Free and Creator tiers are unverified, so check its terms before you ship.

3D model generation · Free tier + paid →
Text-to-3D and image-to-3D model generation with AI texturing; paid plans add animation with 600+ motions. DCC bridge listed for Roblox, Blender, Godot, Unity and Unreal.
For quick text- or image-to-3D props with Godot/Unity/Unreal bridges; free output is CC BY 4.0, so you must credit Meshy unless you pay.

Concept art & 2D assets · Free tier + paid →
Production-focused generative platform for game art: train custom style models on your own assets, generate images, textures, 3D meshes, video and audio. API-first with Unity/Unreal integration.
For studios that want custom style models trained on their own art; commercial use needs a paid plan (free output is personal/evaluation only).

3D model generation · Free tier + paid →
Template-based and AI 3D generator for game-ready props and objects, with browser editor and plugins for Unity, Unreal and Blender on paid plans.
For game-ready props from editable templates with Unity/Unreal plugins; the free plan is personal-use only.

3D model generation · Free tier + paid →
Text/image/multi-view to 3D model generation with retopology, segmentation and up to 4K/8K texture generation. DCC bridge lists Blender, Unity, Unreal, Godot and others.
For 3D models with retopology and engine bridges; the free plan is non-commercial, so shipping assets requires a paid plan.