If talking about for sparring, most modern dojangs drill lead leg cut or stab kicks, which is like a sparring front leg side kick. But when training for sparring, instructors are often less worried about technical form, but speed (both in terms of impact speed and the total wall clock time of the kick).
However, when doing that you generally teach to lift the leg, then travel - rather than the more basic skipping motion (back leg first). The reason is in modern Taekwondo, the first one to get their leg above their opponents in a cut/stab kick race wins, so if you go back leg moves first you move towards your opponent body first - and the opponent can lift their front leg to cut your motion. If you go leg first, they have a leg to contend with (and there are options for that, clashing for one) but it makes it harder. Here's a video example of the motion I'm talking about (ignore the head kick counter to the re-movement, but just the initial lead leg cut kick)