The Retro Fighters wireless Brawler 64 is a simple, solid option if you prefer a modern shaped grip. No rumble and I wish it had some more heft to it though, it feels very light in the hands. The stick has a shorter throw than the original controller (like most modern sticks) so it tends to feel a bit overly sensitive, but it works.
If you want to go the BlueRetro adapter route that opens the door to any bluetooth controller. For something in the original form-factor the official NSO N64 controller feels amazing! Really premium, rumble is fully functional and you can just tap a button to swap to virtual memory pak. Or you could mod an original controller for wireless with the 8bitdo modkit (can even choose whether to keep the original stick box or swap it out for their Gamecube style replacement), though the 8bitdo modkit frustratingly doesn't support rumble outside of the Switch. But I love my original controllers so it's cool nonetheless.
As far as BlueRetro adapters go there are the single-port dongles as someone posted above, or if you plan on having a full 4-player setup you can find multi-cabled BlueRetro receivers which save on power consumption and avoid the interference you get from having a bunch of dongles all paired at the same. I have one of these from GrechTech for N64, tucked away in a drawer on extension cables.
Only issue is there's a
longstanding BlueRetro issue with Switch controllers where pairing more than one at a time on a single unit causes unplayable latency and disconnects, so my current setup includes 1 NSO N64 controller along with 3 8bitdo N64 controller modkits and everything plays nicely together.
More info than you probably wanted, but there you go!
8bitmods.com
shop.8bitdo.com
