Certainly. One early concept that was initially underestimated but turned out to be absolutely crucial to the development of the Internet was the idea of packet switching.
Packet switching is a method of data transmission where information is broken down into smaller units called packets, which are then sent independently across a network and reassembled at their destination. This concept was developed in the early 1960s, primarily by Paul Baran at RAND Corporation in the US and Donald Davies at the National Physical Laboratory in the UK.