Yes, "good" day-trading coins are ones with high liquidity, range and volatility--basically, any coin that has a history of having made big jumps in a short amount of time (you can also see why this is dangerous). Some popular ones are neo, eos, ltc. Do some research on your own, however, choosing coins is subjective.
nice coins I already own, I will try my luck - how much gain in % is a realistic outlook in your opinion? I often read beginners are too greedy!