Pretty much any driftwood is fine for apistos and kuhli loaches.
The more popular types found in pet shops are manzanita, mopani, spider wood, and Malaysian. Manzanita are typically elongated and branchy (often used in wedding decor), mopani is smooth with large, curved knobs, spider wood resembles manzanita but are usually thinner with more branching, and Malaysian is darker with a bark like surface.
There are online sellers for driftwood.
Avoid grape wood which is often found in the reptile section. It tends soften in water (much shorter lifespan than those mentioned above).