Yes. Cut losses short. Let winners run. Position size relative to your TLNW. These are some of the tenets of Prudent Risk Management. That is the only edge available to the retail trader whether now or in the distant past.
There have been trends since markets began within which edges can be found. And there will always be trends in the markets as long as there are people who can't read them!
There is dumb money trading and there is smart money. Dumb money have no edge nor do they know how to find it. Smart money have an edge and smart retail traders (once known as dumb money) can spot the clues of dumb money vs smart money. Dumb money chase dumb trades, smart money seldom trade stupid, if they did trade stupid they wouldn't be sitting on a wad of cash for long, rather they would be seen hanging around the pawn shops along with dumb money hombres. Back to OP's question, yes there are edges as old as Methuselah.
Yes, compounding, ideally 10s of percent per year, optimally 100s of percent per year, and realistically single percentages per year. But, as that means getting it right from the start you have no chance, which is why everyone buys in to the synthetic get rich quick and you can trade with no capital or experience schemes, trying to catch up. The only way you can do that is marry wealth, create you own synthetic scheme (not my recommendation but it's what most choose), or trade lower time frames (now we're talking).
Finding an edge isn't hard. Recognizing the value of the edge is extremely difficult. Becoming a knowledgeable, experienced investor is a journey of 10,000 miles, so to speak. You begin the journey by stepping out of your front door, and 10,000 miles later you reach your destination, which was always at your back door. In other words, you were never far from your desired destination, but it required a journey of 10,000 miles to make the realization. Ask someone if an edge 'works' and you'll get as many contradictory responses as respondents. That's because every person bases his definition for success from his place within his personal journey. Now, to answer the question "Is it possible that an edge/pattern has worked since the beginning of time?", the simple answer is yes. Having better information than the person with whom you trade or are in competition has always resulted in an edge, since the dawn of time. If you are asking specifically about an edge derived from technical patterns that have existed since the advent of modern electronic markets, the simple answer once again is a yes. Several have already mentioned a few. Recognizing their value is up to each person. I'll make an additional comment for further consideration. I'll say that the question, because it merely inquires about the edge, may be misleading to many. Be aware that having an edge and knowing how to use it are very different, since an edge is only useful when applied correctly given so many variables not discussed in this post.
I've handed out the edge to everyone numerous times over the past 11 years. Very few are willing to listen. I no longer will be discussing the edge in trading.
Ain't that the truth!! As soon as you suggest something that's not as simple as pie and requires even a little work, thinking, or study, they're off to a new thread.