I make karaoke videos for my own use, the way I prefer them, which is to have the lyrics presented in complete blocks of verse, chorus, and bridge, making sure they are accurate in terms of in & out points of the original recording artist, not dictating the exact phrasing but instead leaving the vocal interpretation up to the singer. They assume a fairly thorough familiarity with the song.
And even though it's the music and lyrics that are of primary importance for karaoke videos, I do try to use minimal imagery that complements the theme and mood and adds a modicum of visual aesthetics.
Although I make these videos entirely for my own personal use, it would be a shame not to make them public in case others might appreciate my approach and also share the love for some of my favorite vocal artists and the wonderful music they create.
I will usually post a song in the same key as the original artist's recording, but will sometimes post in an alternate key that suits my own range. So if I the key register is not noted in the title, you can assume it is in the same key as that of the original recording artist.
Note that I make my videos from found materials and make no claim of ownership other than the fact of my having conceived of and realized them. Nor do I monetize them in any way. So, if you wish to use them for your own use, you needn't seek permission from me.