I have put this quick list together as this question keeps coming up across many forums. There are many options…
-Lionel 022, 5123 & 5133, 65132 & 65133, 65166 & 65165, 5166 & 5165, 23010 & 23011, 711 & 721, 12080 & 12081.
-K-Line K375 & K376, K763 & K764, K775 & K776.
-RMT / Ready Made Toy RMT99764, RMT99763, RMT99775, & RMT99776
-O-Line Reproductions OLR604 & OLR605, OLR606 & OLR607.
-RossPlate switches from Ross Custom are also direct fit - same footprint - for the above listed Lionel O-72 switches. Ross Also has #4 switches in the RossPlate.
It should go without saying that the Lionel O (& Flyer O) crossings all work as well.