I encountered the term x87 today. At first, I thought it was a typo. Turns out, back in the golden age of computing, Intel added a coprocessor, ending in 87, to their processor chips, ending in 86, to act as a FPU. Sometimes they would neglect it, and otherwise, it was difficult to put both on a single chip. This came even before the original IEEE floating point standard used today.
It is mostly legacy in modern processors, but I found it curious that it has a stack-based ISA, much like Java bytecode. Of course, it may be more fair to say that Java bytecode is much like the x87.
It may also be more fair to call it 'stack-ish', since some instructions don't pop, some push, some pop only one operand, and some can take an operand from anywhere on the stack.
On top of that, it is also a nightmare as a compiler target, for somewhat obvious reasons.