It's quite painful to create transaction paying less than 1 sat/vb
Coinb.in could work, but chances are someone is going to overpay a lot in transaction fees if they're not very careful.
MARA pool has also joined the party
I like it!
From a pool's perspective, I think they have to choose between missing out on transactions because they reject the fee, or missing out on higher fees if users start switching to lower fees. Either way, more competition is a good thing.