Any kind of ordinary light that attracts bugs. The one at that is in place would attract lots of bugs if left on during evening hours. I would think that even the low voltage, solar yard and garden lights would also attract flying insects, perhaps drawing more of them to within the frog's reach. I'm just saying that if you attract insects to the area, the frogs will come. If the frogs have a secretive place to stay, then they will be more likely to stay in the area 24/7.
Eclectic gardening style, drawing from 45 years of interest and experience. Mostly plant in raised beds and containers primarily using intensive gardening techniques.