https://www.magicad.com/

MagiCAD is the number one BIM solution for Mechanical, Electrical and Plumbing (MEP) design used by thousands of companies in over 80 countries worldwide. MagiCAD makes the design of BIM models easier, faster and more accurate.

Tired of manually adjusting rendering parameters every time you switch tasks? This add-on simplifies the process by allowing you to save and load your render settings with ease. Whether it's sample counts, resolutions, rendering engines, or specialized features like ambient occlusion (AO) and screen space reflections (SSR), you can create presets for various scenarios – from quick tests to detailed final renders. Say goodbye to the hassle of recreating settings from scratch. With the Blender Render Preset Manager, you can focus more on your creative work and spend less time on technical adjustments. Enhance your Blender workflow today with the Render Preset Manager – a practical tool for anyone seeking efficiency in their rendering process.

https://pointlesscreations.gumroad.com/l/LiquidPen

Here is a simple Liquid Pen for Blender for all your... Interesting renders!

https://blendermarket.com/products/quick-procedural-terrain

The Quick Procedural Terrain and Water Addon is a powerful tool that allows you to create realistic and detailed terrain and water in Blender. It uses GPU-accelerated procedural terrain shaders and CPU-based geometry nodes to generate high-quality results quickly and easily.

Fab - Terrain Remix Brushes - Landscape Creation Tool for UnrealEngine / Blender v5.2+

https://blendermarket.com/products/fake-diamonds-shader

This product is a collection of 4 diamond shader node groups to let you quickly and easily make a lot of diamonds. These node groups are very easy to use, just use them as shaders, put in the UVMap and you're good to go. The  diamond shaders are, as the name suggests, fake. They are a kind of cheat that mimic the refraction of diamonds but does not actually refract the light. This method renders very quickly, compatible with both Cycles and Eevee, and produces a believable diamond look. You don't have to wait forever to compute all the refraction and reflection of real diamonds.

https://blendermarket.com/products/n_hair_nodes-v2

It's a Geometry Nodes base tool to help you to make hair in blender.

https://extensions.blender.org/add-ons/smear/

SMEAR is a 3D animation stylization Blender add-on, aimed at creation and customization of smear frames such as elongated in-betweens, multiple in-betweens and motion lines. The system is developed as part of the MoStyle ANR Project by Jean Basset, Pierre Bénard and Pascal Barla. It is described in the following publication: SMEAR: Stylized Motion Exaggeration with ARt-direction. Jean Basset, Pierre Bénard, Pascal Barla. Siggraph 2024 Conference Papers.