The TD ThinkorSwim platform is one the most popular and powerful trading software out there. It hosts incredible tools and features to make trades on many markets such as stocks, options, futures and foreign exchange all at your fingertips. If your thinking about getting into self-directed investing or wanting to change your brokerage we definitely recommend you give ThinkorSwim a try, you can get a free 60 day trial here with papermoney which is essentially "fake" money in a simulated market so you can get a feel for what getting into the markets is like without risking your own capital.
A chart of Apple Options in ThinkorSwim
One of the best features of ThinkorSwim is their powerful scanners which goes by the name of "Stock Hacker", this amazing technology allows you to scan the world of stocks to find the ones that match your own criteria. And with a wide variety of stock analysis filters at your disposal, you can immediately pull up a list of stocks that fit your preferred parameters. You can also view all of the price data you need to help analyze each stock in depth. Utilizing this will help determine what you want to trade for the day or longer in real-time!
Here is an example of a penny stock momentum scan filter
As you can see above, there is set criteria to filter the stocks you want to trade such as the Bid Price being above .0004 or Volume being above 100,000. With these awesome scanners you will always find equities to trade, just remember than generally premarket it will be quiet but once it opens at 9:30 EST with the right parameters you will have quite the selection.