Free and Open Source yet professionally powerful 2D animation software. Simulates a cell based animation approach, handles bit bitmap and vector layers.
OpenToonz: 2D Animation
Category: Resources
Meshroom: Photogrammertry
Meshroom is a free, open-source 3D Reconstruction Software based on the AliceVision framework
This powerful photogrammertry tool is available for Windows and Linux
Normal Map Online
This site lets you create normal maps based on images or a height map NormalMap-Online
Poly Haven (Textures, HDRI’s & Models)
Here are two sites with CC0 (public domain) licensed images, one with textures (including bump, normal, roughness, etc) and one with High Dynamic Range Images (HDRI) which you can use to light your scenes. PolyHaven (F.K.A. HDRI Haven & Texture Haven) which also have Models for download
Freesound.org
Huge selection of user uploaded sound effects, licensed under Creative Commons Licenses. https://freesound.org/
Citizen DJ (beta)
Make music using the free-to-use audio and video materials from the Library of Congress
Free Music Archive
This site offers both free (CC licensed) and royalty free (pay once for use right) music.
Anilyzer
Tool for analyzing on-line videos. Allow you to step through animation / video frame by frame. Works with most YouTube and Vimeo videos.