Clear lac (old school neat lac) provide pretty good water protection.
What I do for my more natural looking projects that I want a mellow sheen on is after dying use a thin coat of neats foot oil, then after that drys I have been using sno-seal which requires occasional reapplying but does pretty darn good to repel water. Others that are similer in style to sno-seal are montanas pitch blend, bees natural, picards leather dressing .... and some more I have forgotten about. These all seem to work really well.
I have also made my own with bees wax, parafin wax, and neats foot oil. It makes a whitish paste similer to very hard butter in consistency but when you rub it in it goes clear and soaks in pretty good. This seems to provide pretty good protection. It will feel kind of waxy for a little bit so putting it somewhere warm helps.
If you use these in light coats they dont soften the leather much if any after they are dry. The thing I like about them is they offer protection but keeps a natural feel and look to the leather and can be reapplied when necessary without having to strip the finish off or anything. Oh and its easy to apply without worrying about streaking or anything.