Would like to brainstorm about realistic home manufacturing ideas.

Candles - possible, but much of a market?
Soap - learn a little chemistry and there is some market
birdhouses for craft fair - ?
metal sculptures - no, seriously
cookies, muffins - for humans - commercial kitchen costs a bit, but possible
cookies - for dogs - still need a commercial kitchen for any real volume, but also possible.
Batteries - too much expense, environmental issues

Can You help expand my list?

thank you