My favorite transfer pump is a peristaltic pump. (this type of pump squeezes tubing like squeezing a tooth paste tube) It self primes, it is easy to sanitize, the wine only contacts the tubing, it is extremely gentle like a siphon and won’t oxygenate wine, and I have speed control so I can finesse the bottom of a carboy. Mine came off eBay.
A vacuum pump is useful. I use mine to degas, vacuum cork and start siphons. I rarely transfer with it since I don’t feel a need to do a carboy in under five minutes, and I try to finesse the separation of clean wine and lees.
There are several vendors for oil free vacuum pumps,,, or for full systems with lots of gizmos AIO works.