Yes if you look at old household books there are quite often recipes for infant milk, various concoctions involving sugar, boiled milk, sometimes egg, beef broth etc. You can imagine some babies sucking it down more or less ok, but it must have given the others a pretty horrid tummy ache - or worse. Pap as I understand it was flour and water but I imagine it was whatever the poorest had to hand that was considered nourishing, and nearest mother's milk.
Wet nurses yes but I think they were sometimes a matter of fashion and at other times it was the 'fashion' for mothers to breastfeed themselves, if they could. The whole history and sociology of wet nurses is pretty interesting, there is good article about it here. I do think of it as a rich person's thing but IIRC Oliver Twist was nursed in the workhouse.
Bottles were a problem too and even more than made-up milk might have led to the death of many babies due to not being washed properly, letting bacteria build up. One of the most underrated inventions in history IMO is that of the boat-shaped bottle which could be washed more easily and probably saved millions of little lives.
Speaking personally I feel very lucky I was able to feed my two safely with milk that was able to be scientifically formulated, rather than come from a haphazard recipe, but I appreciate that it's nothing more than a much better version of the old infant milk, rather than anything particularly space age or revolutionary.