But yeah, materials like the rubber in my inner tube... I'm pretty sure my parents wouldn't have allowed such stuff near me as a baby, likewise I wouldn't have been allowed near boxes of matches etc. I also can't imagine I'd ever have decided as an older child that I should try licking a bike tube or the striking surface of a matchbox. And so, I'm about as confident as I can be that I'd never have licked an inner tube in my life, but I can make a good guess from feeling it with my fingers what it'd likely feel like on my tongue.
There's very little where I'd go as far as to say "I cannot imagine what it'd be like", except maybe for things that would involve a chemical reaction, and where I might have some idea from extrapolation with foods - e.g. fizzing, an exothermic reaction, etc., but wouldn't necessarily be able to guess from looking or feeling with my fingers what the result might be. Most of the interesting ones are turned into food anyway, e.g. sherbert dip or sour sweets.
I definitely have had some surprises in later life - I remember first having ox-tongue when I was in my 20s and finding the texture quite uncomfortable, and since high single-digit ages, I've never been able to correlate the texture of liver with something that's edible.
I guess another example is with unfamiliar "exotic" fruits - there are some that would surprise everyone with their taste, but you can guess most of the texture characteristics of a fruit just by looking at it and cutting it into pieces, and you might be able to have a guess at taste from its smell.
Are you sure you never licked those materials as a child?
I'm not sure when my earliest memories date from any more — some of what I thought were memories turned out to be dreams of things that never happened, others have mutated with each re-recollection — but one thing I can be sure of is that I don't remember any of the "stick random things in mouth" stage of my life.
When I look around my room, I find there are indeed things I cannot imagine what it would be like to lick them, but they're all made of materials I didn't have access to as a kid: soft touch rubber.