A Konosuba - Re:Zero light novel crossover might explore the different magic systems. In Konosuba, magic is often misused or has unexpected results, while in Re:Zero, magic has a more serious and often dangerous undertone. The crossover could play with how the characters from each series view and interact with the other's magic. Also, the settings are quite different. Konosuba has a more light - hearted and comical fantasy world, while Re:Zero's world is darker and full of political intrigue. Combining these two settings could create a really unique story.
One possible plot could be that a strange magical anomaly causes the two worlds to collide. Kazuma's group and Subaru are suddenly aware of the existence of the other world. They initially misunderstand each other and get into comical conflicts. But as they start to understand the situation, they team up to find a way to separate the two worlds again. Along the way, they face challenges that combine the elements of both worlds, like the Re:Zero monsters with the Konosuba - style humor.
I'm not entirely sure, but it's very likely. TvTropes is a comprehensive database for all kinds of fictional works. Given Konosuba's popularity, especially in the anime and light novel world, it would make sense for there to be a section about its visual novel on TvTropes. You could check by searching for 'Konosuba visual novel' on the TvTropes website.