I think that small pleccos would be a good choice. By the way, do they have webbing on their front feet? If they don't they are ACFs and they can grow huge and eat whatever they can fit in their mouths. I have known some people to be sold ACFs by mistake and they paid for it when the froggers made lunch of their other fishies. But plecos are good with both ADFs and ACFs and I have two small ones with my bigger ACF and because of the plating that these fish have, she doesn't try to eat them.
I will let you know this. ADFs are very sensitive to a certain fungus, chytrid fungus, that's been affecting the amphibian populations around the world, and they can die from it. I would advise you to get 50% Benzalkonium Chloride from online. The website is included. If your new froggers start to shed in chunks and not eat, it's time to treat them. You would treat them in another container with 9 parts water to one part BC for every other day for about two weeks. Sadly, these froggers often do come sick from the stores.
I would also advise giving it frozen bloodworms as its staple food. Pick out the few juiciest bloodworms and feed them to your frogger through a turkey baster. I do this to mine, but I tend to hide the food so they have to search the bottom for the food. They search the bottome the whole night, that's how driven they are to find all their food.
I hope this helps.