: If your "blocks" are large separate drawings, use the XREF command to link them. This keeps the host file lightweight.
If you'd like, I can explain how to set up within your host file or show you how to automate the creation of Tool Palettes. How To CREATE BLOCKS (Basic Tutorial) - AutoCAD autocad block host file
If you need to change a layer color or line weight for a standard symbol, you only have to do it once in the host file. How to Build Your Host Drawing : If your "blocks" are large separate drawings,
Are you looking to create a (Title Block) for your drawings? autocad block host file
Navigate to the file path and open the hosts file (ensure "All Files" is selected in the file explorer).