As you consider where to make last minute end-of-year charitable donations, consider donating to a charity that focuses on cleft palate reconstruction surgury. There are many amazing causes to direct funds to, but year after year we contribute to cleft palate repair work because the completely life altering bang-for-the-buck is just incredible. There's no "research" being done that has questionable results (if any). There's no massive amount of money per-procedure that has to be raised. There is a simple, inexpensive, life altering procedure that many many many doctors around the world can perform.
The procedure's impact utterly changes a human's life... forever... for the better. Some of the surguries literally save a life (the child is able to finally eat), while some of them provide a path to a completely new life that allows the person to integrate into society and more effectively contribute to the world as someone "normal" who "fits in." Just imagine going through life knowing how a simple procedure could mean the difference between you getting a job, vs. not. A simple procedure could affect whether or not you could be in a romantic relationship. A simple procedure could allow you to have more friends. A simple procedure can change everything.
Perhaps oddly, we don't have any direct personal experience with cleft palates. We resolved to donate to the cause because the bang-for-the-buck just seemed incredibly high when weighing options for impacting humanity in some small way.