Right now it supports up to 16 basic resources (no more room for more belts

Fluids can be extended by adding more storage tanks by the same pattern and connecting the green wire for the pumps.
There are 1+3 constant combinators: 1 for items to be produced and kept available in output chest and 3 for settings you may need to maintain when producing new recipes.
Constant combinators also have descriptions.
There is also an alert sirene if one of the basic resources runs empty.
Later you can upgrade the output chest with drone storage chest for drone delivery. If you want a belt mall just connect all belts, inserters (read content) and chests to the green wire of output chest.
Only use speed modules in assembler! Productivity Modules will get extracted from assembler by the inserters when producing end products (and cannot be inserted again into it... already filed it as bug but they will only fix it when enough time Thread

In action:
https://www.youtube.com/watch?v=EguLJ1neStE
Blueprint is with blue assembler and blue inserters. Just upgrade as you want.