I had some ideas about a game mode where you start with only your ranger and one illuvial you own, then battle multiple stages winning etheral shards to catch an etheral illuvial from your last battle ( or keep and pass on the capture ) that you can only use during the run.
The further you get, the higher tiers / stages you find, and at the end of a successful run you could transfer one etheral you added to your team and make it a real illuvial , paying fuel to start a run ( crypton ) and to transform the etheral ( solon as it's a "craft" ) .
If you fail your run you lose your crypton, if you win you can mint. every X levels, put "checkpoints" where you chose to Exit the run and mint one, or continue to find something better and risk losing everything.
You could get an alternative version ( ethereal for the sake of this post ) of the usual items you'd use for a battle, but usable only for this game mode, and choose to keep them for next run (high tier etheral shards for exemple ) where you'll go all out, or use them right now.
Gives novelty as there's no real rogue like auto-battler that I've heard of, gives more use cases for fuel, replayability, connects with OW and ILV:Z as you need to gear up your ranger and have a strong starting illuvial, and you need fuel. That would be an interesting way to hunt for a good catch without having to farm OW.
If any of you like the idea or have suggestions, i'd be glad to have your input, thanks for your time !