We have two covenants already, CSV and CLTV. they're time locks to control when a tx can be spent. The next basic covenant is CTV, a "UTXO lock", this constrains the TXID so that the transaction is *guaranteed*. This will help us scale via solutions like Ark and Timeout-Trees. My personal favorite is NIC's (Non-interactive Channels), this let's you commit to a lightning channel simply by knowing its Txid + hash. To explain how this would work, I need to withdrawal from my exchange on Friday, I go ahead and commit to making a LN channel with Bob inside my PubKey, and the exchange pays me in their batched tx. Now that I have the commitment, I can at any time, contact Bob to "establish" the channel, with no need of a second transaction.
As for Lyn's comment on how the dev community is split. CTV can be upgraded either to Txhash or Template Key and a lot of devs want to skip step 1 and go straight to the advanced covenant proposals. They've even gone as far as to say that they fear CTV would delay txhash. I want txhash too! But it needs years of more bikeshedding before it's even close to ready. CTV is ready, it's been ready for 4 years.