It might help if you use the botanical (scientific) names. The Bella Palm is more commonly known as the Parlour Palm (Chamaedorea elegans). Any nursery will sell them and you can often pick up multi-planted pots in Coles, Woolies, bunnings etc at a cost of around a dollar a plant – if you want to separate them out.
Borneo Sword (Aglaonema simplex) is also called Malayan Sword. A full on nursery would be your best bet.
Creeping Fig (Ficus pumila) is somewhat less popular these days than it was in the past. The problem with it is that once it get established on say a fence or building, if not kept in constant check it becomes and aggressive and invasive vine come tree – a bit like the Strangler Fig. If you know where some is growing, just peel back a shoot and try and tease the adhering roots off the surface to which it is attached. Trim the torn stem to leave a clean cut and place in about 3 to 5 cm of water in a warm, well light position not in direct midday sun. Once the new roots have grown a couple of centimetres you can then plant it.
Chinese Evergreen refers to a number of Aglaonema species. Chinese Lucky Plant Aglaonema commutatum has proven to be a common cause of poisoning.
Three of the above plants are often sold and touted as aquatics. They are not. They will survive for a reasonable amount of time under appropriate and good strength lighting, but eventually will drown. If you want something you can plant in the gravel that will provide great frog habitat and not mind continuous wet feet, any of the Philodedron species, Peace Lily (Spathiphyllum sp.) and Devil’s Ivy aka Pothos (Epipremnum aureum). Wash all soil from the roots and plant into the gravel so that the roots are at least partly submerged. If you are looking for fully submerged plants, go to the local aquarium centre - Ribbon Weed aka Vallis (Vallisnera sp. Is great for taking up wastes from the water. If you cannot get the dwarf variety then any of the others will do. You just need to take to it with a pair of scissors when it starts to get too long. Periodically pull half of it our and throw on the compost. The remaining lot will bounce back. There are lots of other true aquatics that are quite attractive: Cryptocryne species, Amazon Sword Plants (Echinodorus species) etc. There is also a nice range of emergent plants like Water Milfoil (Myriophyllum species) and Bacopa species to mention just two. There are also somw great small sedge style plants available. One of my favourites is called Scirpus Fairy Lights (Isolepis cernua syn. Scirpus cernuus). It likes strong light though. There is also a variety of mosses that can be grown in a frog terrarium. You can often buy living sphagnum moss or you can collect your own local species from around the place and see how they go. Alternatively, give a Bonsai Nursery a call and enquire what they have available in the way of mosses.
That’s probably more than enough for you to think about but if you have any more questions, please don’t hesitate to ask.
Blue