Since the banning of Cloud of Faeries, Delver has been a persistent top-tier strategy in Pauper. The combination of efficient threats, counterspells, and burn spells is certainly a powerful one; and players are starting to look for different ways to gain edges in the Blue tempo mirrors. A generally accepted way to gain an edge in mirrors is to find a way to go a little bigger. Some people are trying adding some copies of Izzet Boilerworks and Mulldrifter, but perhaps there's another option:
Blue-Red Faeries - Pauper | VIEZEFUR, 5-0 Pauper League
At a glance, this deck looks exactly the same as other Delver builds. Then you notice that there are no copies of Delver of Secrets. Delver is a high variance card. When it's good, it's one of the best cards in the format. When it's bad, it's an inefficient way of trading down with cards like Mulldrifter and Stormbound Geist. Because of this dynamic, Delver is a great Game 1 card that frequently gets boarded out in matchups that aren't about racing.
Consequently, this build just cuts them outright in favor of more interactive spells. Instead of leaning on fast starts from Delver, you have more space for cantrips and cards like Dispel and Flame Slash. This means that you're better set up to interact early and often, ensuring that you can protect key threats like Ninja of the Deep Hours so that you can stay ahead on cards and press that advantage until you're able to get your opponent dead.