My advice, "Dont put all your eggs in one basket" or much better stick on Bitcoin investment while it is dumped.
You said don't put all your eggs in one basket and then suggested the opposite
. (I had to...)Op if you're trying to learn then forex is quite forgiving (especially if you stop trading at news and pull your positions).
Developed countries are generally quite stable when nothing democratic occurs (elections or referendums).
Other than that you could look at coins with good volume or market cap (pairs exchanges will normally suggest). If you can find a repeating pattern then it may be tradeable.