Released on the Nintendo 64 in 1998, The Legend of Zelda: Ocarina of Time is one of the series' most iconic games. A GitHub organization that calls themselves the Zelda Reverse Engineering Team is making good progress on making a PC port for this classic title.
As the project's readme explains, this work in progress project is a decompilation of Ocarina of Time, with the end goal being to "recreate a source code base for the game from scratch, using information found inside the game along with static and/or dynamic analysis." In layman's terms, this means that if you have the assets from a ROM of Ocarina of Time, you can run it natively, which effectively means that the team is reworking the code to make the game naturally work on the PC. So far, the only build the project currently supports is a debug version of Master Quest (a harder version of the original game,) but the team plans to develop support for other versions.
However, companies aren't always fans of their fans poking around with their games' code. Earlier this year, Take-Two went after a team of modders who reverse-engineered the code for GTA 3 and Vice City. They've also issued cease and desist orders against modding tools for GTA 5. Meanwhile, Nintendo is well-known for having a downright hostile attitude towards fan projects, mods, and ports (the Super Mario PC port was very similar to this one). Time will tell whether this Ocarina of Time fan project draws the ire of Nintendo and is forcibly dismantled.
You can find the Ocarina of Time project here, and you can see some of the other projects the Zelda Reverse Engineering Team is working on here. The group also has an official website and a Discord you can visit if you're interested in contributing to their projects.