There actually are a number of such coins having high ROI but yet investing in those coins can be riskier as they might even move in opposite trend. Nexus, Banca, etc might be a good source of quick income.

But, I would prefer you to invest in some coins which are having immense demand currently. You can try BNB because this coins really has got the potential and also is moving to higher prices each day which might perhaps be beneficial for long term holding. Even the current price for BNB is on peak at the start of the bull runs itself so we indeed could expect more higher price in few coming days once the bull runs hit the markets. There are several other coins which too would experience a pump soon so you could try to diversify your investments accordingly.