Deciding on the best mixer for your karaoke will depend on your set up, and I am sure you want to know what mixer to choose, so I will provide some insight to assist you selecting a karaoke mixer.
The first thing you want to do is decide on a budget and if you need a mixer. Often a karaoke player will connect directly to the TV without needing a mixer. Many karaoke players have a mixer built into them so be sure you really need one first.
The advice I offer you when looking for a karaoke mixer is to decide what will connect to the karaoke mixer. Things that collect to the mixer may include the microphone and karaoke player. Decide how many microphones you will be connected and research the connection types available for your karaoke player and microphone to be sure the mixer you choose will allow that connection.
The other thing you need to know is where the sound from the mixer should be going so it can be heard. Most of the time you will send the music and the singing out of the mixer and into an amplifier, but sometimes you can send the music to powered speakers without an amplifier so you need to decide on how it will integrate into your karaoke setup.
You can get compact mixers or a large desktop mixer depending on your needs. Often a small bookshelf mixer will do for a home setup because they do not take up a lot of space. A larger professional mixer may be needed for a commercial karaoke system.
I suggest you read the article Karaoke Mixers and Choosing the Right Mixer because that has a lot of information about karaoke mixers and links to some popular options that may be ideal for you.