The last 2 suck. The first only works if you know the latest ideas.
Three Gambits in the Dutch Defense

They are dangerous enough openings as you don't face them often to keep the memory of the theory fresh. Further, pleanty of Dutch players start eith 1.e6 or transpose into Dutch set ups to avoid those positions.
Staunton Gambit
Krejcik Gambit
Omega-Isis Gambit