The brothers of Delta House -- and by that we mean the pledges -- employ an inelegant but effective method of ensuring that all available securities are included in our portfolio:
Use the advanced search function to scan by price range (all stocks between 'min' and $2, for example, or all bonds between 100 and 150). Choose ranges that will generate fewer than 500 results. Scan the resulting list. If no small 'suitcase' (light for short, dark for long) adjoins a prospective investment, that investment is not part of your portfolio. Buy the quantity your inclinations and capital indicate.
There may be a better method, but Bluto and D-Day stole the wrong test answers so we don't have it.
But don't feel bad for us. We have Mandy.