DappRadar is a useful but ultimately hand-curated list. For a more comprehensive look, https://blockspur.com/ethereum_contracts/transactions https://blockspur.c

DappRadar is a useful but ultimately hand-curated list. For a more comprehensive look, https://blockspur.com/ethereum_contracts/transactions https://blockspur.com/ethereum_contracts/transactions ranks every Ethereum smart contract by transactions, "users," and "revenues." The top 3 contracts with the most number of users in June had 370K+, 210K+, and 88K+ "users" respectively. (Disclaimer: maker)