Not a bike tool but the Stanley 9 1/5 block plane my dad gave me a long time ago. Years later gave me Craftsman jack plane. Then a really sweet Lie-Nielsen 102 low angle block plane. Bought a Lie Nielsen rabbit plane. Those 4 planes are really useful! Everything from serious wood removal to finessing oak end grain.

And funny story re: the 9 1/2. My dad gave my younger brother a Craftsman 9 1/2. On evening, we took our planes apart and compared them. A few parts were different; not in any manner that mattered. All the key parts were not only identical, they were cut on the same machines. Same scratches. Now, over 4 decades later, we both still have ours and still use them.