Rock / Flying
Rock / Water
Rock / Electric
Rock / Fire
Rock / Grass
Ground
Grass / Ground
Grass / Fighting
As always, I'll put some thoughts on every option ranked.
- Rock-Flying truly has the most intuitive typing for this project. Good set of resistances and immunities, flexibility in archetypes, it's truly a no-brainer for a top spot;
- I came around to Rock-Water pretty recently. The thing that truly speaks to me are the design possibilities for the pokemon itself. Outside of that, it's got good resistances and still boasts a good stab combination;
- Rock-Electric is a good balls-to-the-wall offensive typing that offers clear strenghts and weaknesses. I'm a fan;
- Rock-Fire is another offensive one that could be potent, just less interesting to me compared to its electric variant;
- Rock-Grass is the least interesting out of the rock typings, as it has a miserable defensive profile, while still not being special enough offensively to interest me;
- The other ones are as easy as the lack of stabs turns me off way too hard. Ground is a fine, vanilla choice, same with grass slapped on. The only one i really don't like is Grass-Fighting. I just feel like if it gets enough good stabs or utility, it might just drop diamond storm al together. Also, completely unrelated to interactions, I don't see a way to thematicaly tie diamond storm to a Fighting-Grass type without making it too convoluted.
Last thing, big sad that Normal-Rock didn't make it