Post your ideas here and who knows, maybe your idea will be utilized.
Advertising crypto casinos is currently quite difficult I think, the competition is huge, the promotion must stand out accordingly.
If the main purpose of the promotion is to generate new customers and deposits, a classic "deposit bonus" may be the way to go:
For a relatively short period of time (e.g. over the weekend) Luckybit adds a certain percentage to all deposits. The percentage should not be too high, but also not so low that it's not worth it for the players, i.e. something between 5 and 15% of the deposit and of course it has to be capped, e.g. max. 0.005 BTC per player. This bonus will be added to the balance on the side and can be used for games (but not withdrawn).
Of course you have to take care that abuse is prevented, so that a player creates umpteen accounts and thus often takes the deposit bonus.