When choosing a currency pair for trading, you should be guided by your own trading strategy and risk management. In particular, the approach to choosing a pair may differ from the approach to trading:
Trading between currencies in which you are can stay as an investor indefinitely (risk: none).. When choosing a pair, the calculation ais made on the fact that the money is already in this asset, so let it work, not to dust. At the end of the material, there is a small note on choosing a pair for this approach.
Trade on pairs that are expected to rise (risk: medium-high).. When choosing a pair, complex intellectual calculations are made, and if everything converges and the pair's rate grows, then you can really earn more with bots by taking profits on rises and reopening trades on rollbacks. But how can tou be sure that the pair's rate will grow? Not recommended.
Trading on popular pairs (risk: high).. When choosing a pair, the bet is made on the fact that there is good activity on the pair, so the probability of an early execution of the first orders in order books is greater than on less popular pairs. Not recommended.
Trading with the sixth sense (risk: maximum). When choosing a pair, the bet is made on the luck. Not recommended.
The risk in the wrong choice of a currency pair is that if the rate goes down, you will have to be an investor for an indefinite time or fix a loss on this trade, or risk even more and DCA.
You can write out all the coins in which there is a willingness to be an investor indefinitely; combine all coins into currency pairs; check which of them are on the exchange; start trading on them.