Hey everyone! So you may know that gm/id method could be a handy tool to design analog circuits, especially in the first couple of iterations that can take you close to some specifications. Well, I have created some testbenches to showcase how to use it to design some common OTA circuits in GF180MCU, and you can find them in my repo which is here: https://github.com/ChrisZonghaoLi/gm_id_gf180mcu/tree/main. You are welcome to try them out! Thanks!

Thank you very much @Chris.