The 2N3904 is one of the most widely spread switching transistors. There are countless SMT variants available from at least 15+ different vendors in all kinds of packages. Mouser lists more than 50 variants, LCSC more than 80. I picked four devices in SOT23 package at random, trying to balance between more established manufacturers and lesser known chinese sources. Ironically the Nexperia part was the cheapest. The table above lists the four devices and their respective datasheet values. Siko admits to having a slightly slower device while the other datasheets look like they were copied from each other.