My Petsmart and Petco actually have nice selections to choose from, Petsmart actually has their bamboo sticking above water. Petco use to have terrestrial plants that were just sitting in water but the plant was out of the water, I went back on Saturday and they flooded the section again. It does bother me as well, u got kindle grass as well ok my first aquarium, though it barely rotted for months when I decided I needed to take it out.
Watch out for the tubes as well, half of the plants are usually non-aquatic as well. If it looks really cool and isn't Anubias, a sword, java fern with wrinkled leaves, or java fern wenditei or something like that it may be a non aquatic. The best way is to just study your plants, when you go to the store look at the plants and names then search it on the internet.
I think you thought the mondo was an onion plant maybe? It is aquatic, they just call it an onion plant as it looks like what the name suggests.