Having a small but solid library of spice models that can be distributed as a KiCad library would be a great addition for beginners (such as me) with simulation.
I have managed to simulate the default sallen-key example after some tweaking, and after hours of searching I even managed to find a spice model of an NE555 that works with ngSpice.
Even such small things as having to remap some opamp pins of an (otherwise working) spice model easily confuses beginners, as they have no way of knowing where to start to solve it.
Even having a small library with old yelly bean opamps such as LM358 and TL071 and other parts that work directly without tweaking would be swell.
Distribution with Kicad is a problem though. As I understand, the opamp models (as example) do not only have to work with ngSpice (a lot of them don’t due to various issues) it has to have a verifiable licence and be “legally compatible” with KiCad.
On top of that, I think there is a bit of a lack of librarians for KiCad at the moment.