No doubt butcoin is the most profitable coin if invested but if you are searching for altcoins, then i suggest you to explore ripple, bitcoin gold. Both coins are young in crypto market and are showing capacity to become top coins among all other altcoins. Ripple is still cheap, nearly $1/ripple at the moment, 100 couns can be bought easily for $100
Altcoins is more profitable than bitcoins because it can x10 easily + the rise of value of bitcoin means you can get a higher profit when holding an altcoins but more risky that's why you can see if bitcoin rises altcoins will dumped due to switch in USD/BTC of traders and if investors put their Btc into alts they can earn another profit then add up your profit in Btc.