Bitcoin's release process and schedule have become a model for many other cryptocurrencies. For example, Bitcoin Cash, Bitcoin SV and ZCash also have a hard emission limit of 21 million coins. There are other coins such as Litecoin that use a similar structure but have a larger total number of coins.
However, there are cryptocurrencies with a completely different approach to issuing coins. For example, in Dogecoin (hi Elon), the emission rules remain the same for each new block forever. This means that the number of tokens in these networks is practically unlimited. It is believed that this model will help maintain a stable price and make their coin more suitable for use as a medium of exchange. However, only time will tell if this theory comes true.
Many coins and tokens fall in between these extremes. Most of them are based on the Ethereum
platform, and although they have a maximum issuance limit, this limit is often very high. For example, the total supply of the Tron network's native coin, TRX, is limited to more than 100 billion.