Depends on your goals. If you target long term and maximum ROI, only target micro caps, under 1mil. There are some of them completely under the radar, cause devs struggling with crypto related marketing, on the other hand they have working product, real world usecase and most importantly customers.
If you seek safety, only purchase BTC for now. Any other mid/high cap coin is no better than BTC. And talking about blockchains (not app tokens), youll never know which one will be actually used in the future by business or retail. In terms of apps, its always better to buy them instead of blockchains, except BTC. Cause dapp can move between different blockchains. Only matters their own business.
I usually compare it to Betamax and VHS thing. Only 2 formats who competed the market. Even in their case you had 50/50 chance to pick the right one. In crypto its like 1 in a 100 or even 1000 chance. On the other hand, you can purchase a small video store share, which can easily trade both and in the end will only sell VHS. In the future will trade CD, DVD, BLU-RAY. In the end becomes a huge electronics store, or just a great local store. No matter if you purchased it at under 1mil cap and in the end it becomes 10mil or a 100mil. Youre still in profit.
So in any case, either purchase BTC or under 1mil Dapps. Which have working product, customers and a great blockchain usecase.
I wont hype my own list of such micro cap coins here. You should make your own analysis and try to find such projects yourself. I believe its possible in a matter of couple days/a week. Then maybe another week for more in-depth analysis of top choices. And youre good to buy 2-3 projects for a long term hold.