I like your question very much. It is of course a tall order for the guy who is willing to answer this question. The answer can be based on pragmatism and known facts of solid state chemistry and I shall advise to do that. You must consult books on solid state chemistry where numerous examples of possible known compounds. If that does not satisfy your curiosity then move to the inorganic structure data bases like ICSD. Your formula immediately suggests perovskites and double perovskites, there are plenty of them in these databases and probably that will satisfy you. If not then go ahead with other possible structure types and read the literature by keeping a periodic table on your desk. You will then immediately know what are the compounds you can easily make. You will see yourself many possible compounds. This is a realistic approach and if I were you I would follow this approach.

But of course there is another approach that I call "solid state engineering" or "ab-intio or first principle" approach. This will definitely be preferred in future. You then first buy very expensive and powerful computers and start solid state chemistry there first rater than in your laboratory with your dirty lab coat. You can then even have smart dress with bright color tie! I shall soon come back to your discuss in more detail about this approach which definitely preferred by your researchers one day!

If you wish to adapt this modern "solid state engineering" or "ab-intio or first principle" approach then you somehow get all the necessary available codes like "VASP" and many others. You don't have to know much about the quantum chemistry, these programs will guide you even if you are "blind'. These are all black boxes anyway. Now you start with your imaginary compound that you wish to produce in your lab. Now calculate all these parameters (you cannot call them parameters really, they are all holy numbers obtained by ab initio calculations) and try to calculate energies and stabilities of your phases!! You are sure to produce a mess at first. They you will learn the trade slowly. By that that time you will be an experienced scientist and you will no longer like to think and synthesize and face all trial and error hazards and dirty your lab coat. You will hopefully produce many papers based on your calculations of imaginary objects which no one will be able to produce in a synthetic lab.

@Shanu, I advise you to take the pragmatic approach. I have worked many compounds with the formula you suggested (if you allow a bit generalization and allowing absence of one component and doubling the O occupancy). You can start with ReO3: an wonderful compound: an oxide metal which conducts as good as Ag and shows negative thermal expansion (NTE). You can work on ScF3, an insulator which shows even better NTE. You can work on perovskite manganites, multiferroics. You can produce double perovskites with formula ABCO6 and you will produce disorder of two different octahedra that will help you to produce even more novel properties.

@Shanu, I shall come back to you. Meanwhile you can have a look in the RG all about these works.