https://wallet.ambire.com/ provides staking of the ADX and WALLET tokens using a receipt token model.

receipt tokens:

WALLET https://etherscan.io/address/0x47cd7e91c3cbaaf266369fe8518345fc4fc12935

ADX https://etherscan.io/address/0xb6456b57f03352be48bf101b46c1752a0813491a#tokentxns