If there was a reliable source to tell us when some token will rise 50%, then we would all have already bought before it so the sudden jump wouldn't have happened.
Seriously though, after the price movement I would start with Google News. If we're talking big changes in
Cardano or
privacy coins, you'll find sources there. If nothing is there, Twitter. After that, you can look at the token's official site, bitcointalk, reddit, but really there is no single oracle with this knowledge.
Some movements are due to an event like the ANT->NEO rebrand (that made me happy) or Elon Musk's Twitter (Doge), but others will always be opaque. Some early investor cashing out in a hurry, some Telegram pump group.
I stopped looking for the
Next Big Thing. Don't get me wrong, it would have been nice to buy ADA or DOT in early January and HODL. I just don't think it's easy to have an edge over all the other speculators on that kind of timescale. If we're talking seconds or less, then yes the markets are still very inefficient.