Suckers are by far the best live bait that anglers use for muskie up north. Use the big suckers and fish them on a quick strike rig to prevent muskie from swallowing the hook. Sucker fishing in the fall is very popular as water temperatures drop below the 50 degree mark and the bite will continue until the lakes freeze up.
Chubs can also work very well. You need to make sure to get the biggest chubs you can find in the bait shops though. Many of the bait shops will carry smaller chubs that won’t be as good for muskie.
Shad also work great for muskie. On many of the lakes down south, anglers will cast net shad and then use them as bait.