Any structure that you are well familiar with can be used as a memory palace.
Fingers of your hand. Points on your body. Locations on your work desk, your yard, you car (even just the steering wheel is rich in possible locii), the building where you work or study or a painting.
A journey is a linear form of memory palace so, your walk to the bus stop, Your ride to work etc.
One of the advantages of a memory palace is that it exploits structures you have already memorized. But if you do the extra work, you can invent your own. I like to draw mine.
Memory palaces do not have to be spatial. Any structure that you know well and can traverse systematically will work. A story, a song, a tune or even a family tree, gaming scenes can all work.
This thread has a lot of info. Lynne Kelly - Memory Palaces