What does this mean? Are you just venting to interact with fellow investors or do you really want to ask about the mainstream? Mainstream means something that is mainstream. What this means is that perhaps you are asking about what coins investors usually hold, is that right?

If yes, then this will depend on the investor. However, I am sure, if they are long term holders, they will choose a coin that has had a very good response in the market, has had significant technological developments and projects, and is still running and developing the potential of the coin. The altcoins that they usually take are those that already have a fairly high market cap and are top coins. Maybe these include ETH, BNB, Matic, SOL, XRP, and others. These are altcoins, because Bitcoin is the main crypto investment.

However, there are also those who like to invest in high risk coins, namely new projects that are likely to be hyped so that they can get high returns quickly. but this is very dangerous for newbies who don't really understand the steps.