Useful links:
Official site for Mandelbulb3D: https://mb3d.overwhale.com/
Download site for Mandelbulber, a 3D open source fractal program. Works on Windows, Mac and Linux: https://sourceforge.net/projects/mandelbulber/
Fragmentarium 2.5 is a 3D fractal program derived from the original Fragmentarium project: Fragmentarium
JWildfire is a popular fractal-flame based program done in Java. His author also keeps MB3D alive: Jwildfire
JwildfireSwan on Steam: https://store.steampowered.com/app/3529700/JWildfireSwan/
Fractal Forums https://fractalforums.org/index.php
Incendia Next. An awesome 3D fractal app. Incendia Next.
FPT (Fractal Path Tracer) Interesting project on 3dfractals: https://github.com/adam-pa/FPT
Hyperion is a high-performance generative art tool built in Godot for exploring and recording complex fractals: https://github.com/snicker02/Hyperion