What tool for connection diagram - MAX485 I2C PCA9685 MCP23017 ULN2803 JMRI CMRI

Welcome aboard! For parts not in the core library a google search of the form “fritzing part CH340g” will often find parts. In this case in this forum post (although I don’t know how usable the part is):

The other parts have similar hits. If the parts you find don’t work, feel free to post with a link to the part and one of us will likely take a look.

Peter