Hello, I use "Supalube" made by Loctite, it is waterproof and contains Teflon. It comes in small handy 85ml tubes. It's quality stuff but at about £9 it's expensive for what it is, although you are only using small amounts so in the long term it's not that bad.
A cheaper option, and probably just as good, is to have a visit to Halfords and look at their bicycle stuff, they have similar products for around a fiver.
You can use any grease realy but the stuff I've mentioned is very "claggy" and doesn't fly off the gears as they operate. I've had other greases fly off and contaminate the areas of the reel where you don't want it, spindle pinion and bearings for example, which slows the reel down.
Regards Ian