Hey Twig, good to see you again! Forgot your itch.io password? Hopefully you made a backup of your Serenitrove save file.
About the relic ideas, thanks for sharing. I get what you're going for, but I do think those effects might be a bit overpowered, especially since relic bonuses are permanent and apply to every turtle, even when nothing is equipped. That makes balance a lot harder.
The plan right now is for relics to work as sets. If you collect the full set, you get a minor boost to stats. So for example, 2x2 mining would be way too strong as a permanent relic effect, but it could potentially work as a rare accessory or tool, with some kind of significant tradeoff. +1 regen sounds a lot more reasonable, and I like the direction of the accessory slot idea too. That might work as a full set bonus, maybe after collecting 20 relics in that group.
Anyway, these are just early ideas and nothing's final yet. Appreciate the suggestions!