I'm wondering, are there any other planned or existing crypto, other than hex, with incentives to "lock" coins, thereby reducing selling pressure?
Neo.
Tezos.
Those are the few and there are many others. Trust wallet has that feature for staking coins.
https://trustwallet.com/staking/The longer we do the staking, the more rewards we get from them which could really attract holders to put their cryptos on their trust wallet.
I'd find this very effective and a sort of encouragement for those who want to hold for several years. Maybe I'm not like them but this is a good option and usually, I do staking during the bear season while waiting for the Bullrun to comes.