You might get away with something like cherry shrimp, though a DG would most likely eat baby shrimps. Some might survive if you plant this tank heavily too, and adults would stand more of a chance with lots of places to hide. Amano shrimps would be a good, if less colourful, choice as they are bigger than cherries.
Be careful about frogs. Dwarf frogs are the only option in a tank this size, clawed frogs get way too big. make sure you know how to tell the difference as some shops haven't a clue and sell clawed as dwarfs.
Frogs are quite tricky to feed; they are almost blind and find their food by smell. By the time they've found it, the DG and shrimps might well have eaten it all. When I had frogs in the tank with a betta I had to make a feeding station from a terracotta plantpot. I put it upside down and cut small frog sized holes in the rim (now at the bottom). There was a stone over the hole in the pot bottom (now facing upwards) and I lifted that off momentarily to drop the food in. I did catch the betta inside the pot, they can obviously get through smaller holes than I thought.
Frogs should not be fed exclusively on bloodworm as you'll see stated on some sites. They need a specialist frog food as the staple; I used Zoo Med frog and tadpole food.
Something else you need to be aware of. I have mentioned that frogs have very poor eyesight, and they can mistake a fish for food. One of my frogs bit my betta's tail so badly he got finrot. I saw the betta with a frog hanging on to his tail towing it around the tank.
And yes, I am trying to put you off frogs. They do much better in a tank of their own.