Can we create custom "add mesh" functions?

[Zemasu]

Adding a plane, assigning mirror, shrinkwrap, solidify and subdivision is quite a time consuming process, i know that blender can do nearly everything with add-ons, is there a way to “save” that custom mesh, and then add it with a simple Ctrl+A -> add “custom mesh”?

[NP5]

Welcome to this site.

Not quite. if you have a basic set up that you will use often you can open a new file and append in the object from another file that can be made and named ready to be easy to find and do that with.

There are built in add ons you can activate that have more shapes as primitive starting points too. So Doubtless if you know how to make add ons you could make a custom variation of that for your own common items to a certain stage already made.

There is coming a new library like feature which will probably make it even simpler. Not quite ready yet.

[FedPete]

You are capable of creating a Blender startup file. Michael will explain that somewhere in his course.

So you can add a predefined object into a collection, ready for reuse. Every time available at startup.

Some help here: https://twominutetuts.com/tutorial/startup-file/

Or you make a .blend file library, Put here all your predefined objects, and FILE > APPEND into a new project. These techniques will be explained. But if you are a starter, then to be honest, it is not that important process workflow for now.
I had the same thoughts, very early in the learning process, trying to organize things. But it doesn’t support you enough in the working, project management process.

What really helps you, is to name objects and data objects correctly. Clean mesh, create collections. Good material definitions, Clean UV-Maps, low Poly if possible. Good project files and folder structure…
image examples, good version control.