Several cryptocurrencies combine a supply cap of less than 100 million with a protocol system and rules similar to Bitcoin (such as its consensus mechanism, governance, and issuance policy). Here are some notable examples:

🔒 Coins with a 21 million cap (matching Bitcoin)

· Namecoin (NMC): Forked from Bitcoin’s code, it uses proof of work (PoW) and has a cap of 21 million coins. Its system is designed to provide a decentralized domain name system.
· Zcash (ZEC): Known as “encrypted Bitcoin,” it has the same 21 million cap and halving cycles, but uses zero-knowledge proofs to make transactions completely private.
· JunoCash (JUNO): A proof-of-work (PoW) coin focused on mandatory privacy, with a cap of 21 million. It targets CPU mining rather than specialized equipment.

⚖️ Coins with different caps and distinctive governance systems

· Decred (DCR): Its cap is 21 million, but it differs fundamentally with an on-chain decentralized governance system that combines proof of work (PoW) and proof of stake (PoS). Coin holders vote on protocol upgrades and the development budget.
· Litecoin (LTC): Often considered “Bitcoin’s silver,” it has a cap of 84 million coins (less than 100 million) and uses a different proof-of-work algorithm (Scrypt), with an issuance mechanism similar to Bitcoin’s.

🆕 Newer coins with caps below 100 million

· Neptune Cash: A Layer 1 protocol that uses proof of work (PoW) and has a hard cap of 42 million coins. It focuses on privacy and resistance to quantum computing.