Ethereum's alternatives and competitors. See how Ethereum compares to similar products. Ethereum's top competitors include Solv Protocol, Radix, and Avalanche. Solv Protocol operates as a one-stop platform and a decentralized liquidity infrastructure for creating and trading nonfungible tokens (NFTs).
In my opinion, BNB is the biggest competitor for ethereum in all the aspects and for far in the recent years BNB is gaining momentum while ethereum is somewhat stagnant on its growth due to external factors like switching from PoW to PoS and even after switching the gas fee for token transaction is still on the expensive side which force the token projects to look for alternatives and that's where BNB stands as first choice.
Maybe what the OP means is not about market capitalization but a large ecosystem so really now Ethereum is bigger than other similar altcoins.
Look at NFT trading is on the highest Ethereum network, I'm not so sure about other altcoins then there is nothing similar to Ethereum right now unless they are a lot of clones or even on the Ethereum network.
Now a lot of the L2 is processing from ETH network to L2 to be bridged.