https://codeberg.org/maxime-andre/rv32
Write your own virtual machine
Uxn
RARS -- RISC-V Assembler and Runtime Simulator
https://github.com/cnlohr/mini-rv32ima/
https://github.com/racerxdl/riscv-emulator
https://github.com/edubart/riscvm
picorv32
About the Testing of My Simple RISC-V Core (regymm(Peter Gu)'s Blog)