I've got a couple of Tolumnias mounted on drift wood. I would think that anything suitable for mounting would work well enough especially if you put a pad of sphag under the mounted plant. You will need to monitor closely to ensure that whatever you choose gets sufficient water to meet its needs. In hot summer, that could mean watering multiple times a day.
I prefer to mount orchids that have pseudobulbs. Things like compact cattleyas, mini-cattleyas or encyclias. You can water them often if you wish but they can also survive for a week or more without water if you need to leave them. Orchids like phalaenopsis need to be watered at least every two days if they're mounted.
most orchids are usually found growing on trees, rocks and moss on riverbanks....
you are in a grow zone where you can grow orchids outdoors, so mounting an orchid is easy in your environment because you have high humidity in your atmosphere and you do not have frost.
Most non-terrestrial orchids can be mounted on "driftwood", but whether a particular one will like it will depend on your growing conditions. Tolumnias and other twig epiphytes tend to be quite tolerant of (and indeed demand) drying out, so they're a good start.
Also, driftwood picked up off a beach usually has ridiculous levels of salt in it which will kill your plants, often even after significant soaking.