General Cards that are p1p1 but are not GRBS?

What are some cards that would be common p1p1 in most cubes, but aren’t GRBS on the level of jitte, TNN, mind twist or whatever? Basically, high powered cards that have some play to them.

I ask because an idea I am toying with is a singleton cube but with another stack of “rares” that are inserted into boosters for some excitement, variety, and healthy variance for the less-spikeish
 
Importing some things from the Scarab God Scale over in #32







Regarding whether they fit in that theoretical rare pick slot I mentioned above, I'm wary of colorless cards being an easy pick for every deck and not an interesting p1p2 or p1p3 decision.
 
Here is a rough idea of how I'd use this:
Start with standard 360 cube or similar.
Power level probably ought to be something middle-ish (like Sigh's cube maybe)?
Play it normally, but occasionally optionally include 1 extra "rare" card in each pack that is randomly picked from a pool of 100 cards that are slightly more pushed but still interesting and buildroundable (tm)
 
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