These wallets are no longer maintained, but safe to work with. If a wallet stops working we will try to fix it.

Groestlcoin Armory wallet
Armory is an advanced Groestlcoin client that expands its features for Groestlcoin power users. It offers many backup and encryption features, and it allows secure cold-storage on offline computers.
Groestlcoin Multisig wallet
Groestlcoin Multisig is an advanced yet easy-to-use wallet featuring speed and simplicity, enterprise-level scalability, and strong security. It supports BIP32, multisignature transactions, offline storage, multidevice synchronization, and encrypted electronic and paper backups.
MultiGroestl HD wallet
MultiGroestl HD is a lightweight client that is fast and easy to use. The extensive help makes it an excellent choice for non-technical users.