Generally, you're better off investing in a more established choice, in terms of safety, of course.
However, every project started somewhere, and most top 100 coins weren't in the top 100 when they started.
Simply put, you could assume a newer project has a higher risk of failure, and thus higher risk of losing your investment.
But, assuming you invest in a useful project, and it succeeds, you've got a higher return.
There's plenty of great projects that are out of top 100, and I personally invest primarily in those.
However, you must ensure that you take the time to research the projects you consider investing in!
You can read
this thread for some general tips on what to look for.
While I personally believe crypto is far, far from it's end point, we can still safely say that Bitcoin going to 100k/bitcoin would be huge, considering it'd likely drive the entire market with it and therefore the entire market cap would 10x.
At the same time, a much smaller and newer project, could 10x without it barely affecting more than a 0.01% of the market, potentially.
However, avoid going too low, since projects with very little volume are easily manipulated.
Also consider that a $1,000 investment in Bitcoin, and it somehow manages to surge to 100k each, would still 'only' give you $10k.
$1,000 in a small project however, could surely end up giving you $50,000 if it's done well.
(although some believe those times are over).
The further you go from the top, the more 'dangerous' it becomes, there's constant shilling around many small and new projects.
You are in charge of your money, and it's up to you how far you'll dig into a project before you invest in it.
If you have time and patience and truly find some great projects, then you should invest in those.
However, if you don't, you might be better off investing in one of the top coins.
(although many of those aren't really worth to be there in my personal opinion).
There's no guarantee any coins on top 100 will stay there.
Crypto is volatile, and % gains that could happen in a year on the stock market, could happen over night in crypto.
This also works in the other direction(loss).
So, simply put, if you want a safer crypto investment, go with top coins(Bitcoin/ETH/Monero I'd say).
You can still lose, but it's not the same risks that applies to smaller coins.
And, don't let someone tell you what to invest in - you can hear of projects, but still, make sure you read!
(again, some tips in the thread I linked earlier)
Final note, even if a great project is out of top 100, it could be a very limited use case.
If you find a great project in an early stage, it could very well give you 50x on your investment, without ever entering the top 100.
What matters is the market cap, if it goes from $1m to $10m, that's 10x - although with such a very small market cap, it's still a very, very risky investment since likely someone is in control of a large amount of the coin, or it's an easy target for a 'pump and dump' - however, case is still valid - it's 10x your money, while still being far from top 100. With such a small market cap, there's likely very few people there to buy from you aswell.
In my opinion, many projects are severely overvaluated currently. There are so many projects valued at hundreds of millions of dollars, for no apparent reason.
Be careful and make sure you invest into something valued, because who knows when the purge will come (it bubble).
There are many great projects outside of the top 100's that I'm certain will one day enter the top 100, however, in general, these projects are in early stages and therefore, it's waiting involved.
To summarize, if there were some clear ways to gain money, everyone would be doing it.
The market is bleeding and has been for a while.
There are still projects that has increased, 50%, 100%, 200%, just in the past days.
There are plenty of projects that will increase 500%, 1000%, 2000% in the soon future.
It's up to you to find them.
There's also plenty of projects that will only continue losing value.
It's up to you to avoid them.
High risk, high reward!
