That's kind of hard question to answer. Actually nobody knows what altcoin is going to enter in the top list, even it isn't suggested to invest all your money in one coin, diversification is the fact everyone need to follow. There are many altcoins which have potentiality and positive signs for shine in future, so it hard to pick only one out of these. But if i have to pick one then maybe arbitrum is the one. Not lesser known but not so much popular yet. This is another altcoin which came with its Blockchain to solve problems and going to reveal its advance technology in front of crypto market and has strong community, with dedicated team who are working for make things become easier than before
You cannot say it hard because, there are lot of coins which are highly inspired us from bottom to top list lets say like MATIC, SOLANA, ADA... and so on the thing is we have to invest based on the utility of the project lets say it has be essential in our daily life.
There are numerous project in crypto these days as technology evolves more and more projects will be released for this bullrun I bet on AKASH NETWORK this coin has already started to dominate in networking sector just have a look on the utility of the project.