Take note that ETH is an altcoin and almost or all exchanges listed this coin. Regarding with the others it depends on its team whether it will be listed in known exchanges. Basically, BTC and ETH proved that they're the kings in crypto that's why it is easy for us to trade with it.

In our country(PH), most of us are using an app(coins.ph) wherein it has an option to convert not just BTC and ETH, it also hsve the option to convert BCH and XRP to our fiat.