Lots of lightning projects interest me.

-Any development that could improve privacy.

-New apps to improve the user experience for non-custodial users.

-Things like Greenlight that improve the options people have when figuring out how custodial they want to be. There's quite a big spectrum on Lightning for how hands-on or hands-off someone wants to be, and I think the more options, the better.

-Lightning infrastructure- all sorts of liquidity providers and so forth.

-I like Fedi; I think it could help improve privacy for the network and give a more private way to incorporate custody as well.

-Taro to bring stablecoins to Lightning seems like a good fit to me.