I don't know about systems, but there are proven approaches to active investing. "Buy and Hold" or value investing. Growth investing. Income investing. In each of these, one would research companies that meet criteria that one sets. E.g. in value investing, one would look for undervalued stocks with steady solid balance sheets, good market share, and solid leadership. Growth investing calls for newer companies, or existing companies in the midst of expansion and one would look for companies with decisive leadership in market share, niche products with high demand and can't be matched by competitors, etc. Income investing is typically stocks with a track record of steadily paying healthy dividends. These are all active investing approaches, and they are not exclusive of each other. One could easily invest in growth stocks and balance that volativity with positions in income and value stocks.
There are very few people who can consistently beat the market. Even legendary investors like Warren Buffet make the occasional bad call. Buffet is probably the greatest value investor ever (IMHO). He has said that he doesn't buy stocks any more, but instead buys companies. His stockholder letters for Berkshire Hathaway are great reading. The one I read explained why Berkshire Hathaway began investing in insurance companies. He seems to have a knack for evaluating companies and determining whether they're his sort of company. I'm sure that he has a staff that pulls all the balance sheet, SEC filings, and does market research on them. That's a lot of research that goes into his brain and results in a buy/no buy type decision. If you want to be the next Buffet or Gordon Gecko, then research how to become a broker. Make a plan on how to develop and grow your business.
For everyday investors, Buffet recommends index funds. (Research his instructions to the trust which will manage his wife's inheritance in the event of his passing, and research 'The Bet'.) Bogleheads (internet personal finance group based on forums at bogleheads.com) revere Jack Bogle, who created one of the first index mutual funds (tracking the S&P 500) and opened Vanguard which is a brokerage specializing in mutual funds, where the funds actually own the brokerage, so the brokerage's fees are extremely minimized. There are a number of personal finance, financial independence, and frugal living communities on the web, and most of them make no secrets of their ideas and methods. So if you are interested in that sort of system, start with researching FIRE (financial independence, retire early).
But I think what you're asking for are methods to automate company valuation. Balance sheet valuation is probably the most automatable part. But beware, risk abounds in investing. The idea is to balance risk with reward and to hedge against some of it through asset allocation and rebalancing. And keep in mind that online brokerage hire teams of programmers to develop systems that gather, analyze and present such information to the customers, for a fee of course. And algorithmic traders have systems that assist them in capturing some of the profit available in predicting index fund rebalancing. Theirs is a world of competition, trying to beat the clock, where fractions of a second mean millions of dollars. So if you're interested in that type of system, those are avenues you could pursue. And if you find a way for an average investor to beat the algorithm guys, you'll probably be a household name. This route would call for studying economics, software engineering, and math/computer science.
The only foolproof methods I know of to make money in the market are illegal (insider trading and fraud), impossible at our current level of technology (time travel), or of unknown veracity (clairvoyance).