I'm new to indoor gardening and have a small variety of plants, including an anthurium, prayer plant, philodendron, a couple varieties of croton, etc. I have been noticing damage to leaves but can't seem to find a culprit.

1. There are brown slits on leaves on various plants (anthurium (pictured), philodendron (pictured), and also on the prayer plant now (not pictured)). Some of the brown slits are small, but you'll see on the anthurium, the damage to the leaf was quite extensive. (This was one of the smaller leaves on the plant.)

2. There are small brown stipple-like dots on the philodendron (pictured) and also the prayer plant (not pictured).

3. Little chunks that look like they were eaten out of the philodendron leaves (pictured).

Any idea what might be causing this? Thrips? Spider mites? There are no other signs of either. I've cut off the buds on the anthurium and disposed of a dozen leaves from the philodendron for good measure, but I don't seem to have thwarted it.