One way to estimate network size is total amount of DGB core wallets downloaded from GitHub.
A core wallet is an application that lets you securely store, send, & receive DigiByte's while also maintaining a full copy of the blockchain, helping to keep the network decentralized and secure.
The DigiByte Core wallet is the full node implementation that downloads and verifies the entire blockchain. It provides maximum security and helps support network decentralization.
Core wallet users can participate in voting for network upgrades and run DigiAssets nodes.
For more lightweight solutions, you can try DigiByte mobile wallets available on iOS and Android, or use one of the various supported hardware wallets like Ledger, Trezor, or KeepKey.
Visit the official DigiByte website for more information about all wallet options.