There are quite a few ways to add moisture into the air without a humidifier
A few things that can help add moisture are hanging your clothing to dry. hang drying your damp clothes will add moisture to the air over time as it evaporates and it will make your house smell like fresh clothes.
Another thing is a bath, allow the water to cool off and leave the bathroom door open, the steam will add moisture to the air as the water cools.
This might seem silly but putting bowls or vases of water out on the windowsill on a sunny day mill moistens the air as it evaporates.
You can also get houseplants, moisture evaporates from the leaves and stems of plants. transpiration can help increase the humidity in your home.
not sure if this is the answer you were looking for but if so im glad i could help. have a great day!