Glimmer (GLMR) is the native platform token for Moonbeam. It is a utility token, serving the same purpose as ETH serves on Ethereum, plus added Polkadot functionality such as staking and on-chain governance functions. Read more about tokenomics here.
Moonbeam Tokens and Tokenomics
Moonriver (MOVR) is the utility token of the Moonriver network, the permanently incentivized canary network to Moonbeam. New code ships to Moonriver first, where it is tested and verified under real economic conditions. Once proven, the same code is shipped to Moonbeam on Polkadot.