There's also the actual Shadowcaster from Inner Sea Magic. I don't know how it compares to the 3.5 Shadowcaster, but there it is thematically. A number of other options exist too, of course.
Believe someone attempted one in 2012 or something.
But well nowadays, there are other options when it comes to people who wants to focus on shadow magic.
Oracle with the shadow mystery does everything a shadowcaster did...better with cleric spells on top of it + shadow themed bonus spells.
Not everything... it does not have the Shadowcaster's quirky but interesting not-exactly-spells system (that was one of the major disappointments of the shadowcaster conversions I've seen on this board - making them just a standard caster with shadowy theme kinda misses the point of making a shadowcaster class conversion) and it adds on divine and curse thematics that may not be desired.
I'd search for Peacenlove (sic) and shadowcaster. Check the 2014 version, though you need the 2012 version as a reference for path masteries.
EDIT: Ah, if one is willing to compromise on fluff and spellcasting, there is the possibility of a Shadow pact Avowed (a class I can greatly recommend in general).