Victoria Morrisa wrote:
Do any of you have recommendations for a really good oil-free leave-in conditioner?

Victoria what are you endeavoring to accomplish with the aforementioned?  The only "leave-in" conditioners I use on set are to control flyaway hair during photo shoots and video sessions... Those being CHI Silk Infusion and FAROUK Silk Therapy...  with the later being my current choice since the CHI product is heavily scented.  Keep in mind these are not for long term maintenance.

As for "Oil Free"? Victoria nearly all hair product which is in liquid form contains lipids... I believe if you are experiencing a buildup of product it is likely diamethicon or it's alcohol diamethiconol.  These are silicon derivatives which are ubiquitous in nearly all hair product. 

Best Advice? Consult with a tenured cosmetologist and if your hair is subject to harsh color product seek out an experience colorist... Everyone's hair is different and there are absolutely no universally "good" products for the wide spectrum of needs.

Hope this helps Victoria or is at least food for thought...
I wish you well on your journey...