​Looking for small side business ideas I can work on while I work my 9-5 job

Hello! I graduated with a degree in mechanical engineering and have been working for almost exactly one year now.

I recently realized how much free time I actually have outside of my 9-5 job and that I would be willing to spend a few extra hours every week building a small business.

I am looking for ideas for side businesses I could work on, but they do not have to be related to my degree. I have strong experience in 3D printing, Arduino, and radio-control planes, and I love the idea of searching for small clients and building relationships. I was thinking of doing something as low-level as cleaning people’s trash cans in suburbs, cleaning gutters, or drone photography. I would also be willing to spend some time/money to complete some certification courses to cater to more niche fields.

My motive here is mainly to make a little more money, but I love making small connections along the way and just going through more experiences in life. Please let me know your opinions even if you don’t think your opinion matters or it is small!