Realistically, there would almost certainly be a Starfleet Special Operations division. In the canon, there is something called Starfleet Tactical, but we don't know much about what they do.
Given that the only explicit member of Starfleet Tactical that we've ever encountered was Shelby in Best of Both Worlds the only explicit parallel that can be drawn would be to Military R & D units like DARPA or the US Army's Test and Evaluation Command.
Ro Laren graduated from a program called Advanced Tactical Training before returning to the Enterprise-D and then defecting to the Maquis; it's possible this might be a special operations division a la the U.S. Navy's SEAL Team Six or the U.K. Royal Navy's Special Boat Service.
Considering that "tactical officer" is used to describe officers (usually security and/or armory but other options are possible) assigned to operate the primary weapons on the bridge of Federation starships and that the Chief Tactical Officer is often high up in the chain-of-command of most starships, I've typically assumed that Advanced Tactical Training was (at least in part) related to advanced starship handling, in addition to combat training in general and at least some training in undercover work (though I would expect Advanced Intelligence Training to do more of this).
That said, I am in favour of Starfleet having specialist forces designed to deploy at minor unit or sub-unit level at short notice and Starfleet Tactical could easily have some of these within its jurisdiction (given that most of the team wasn't engineers, Lt Larkin's unit at AR-558 should be a decent candidate for one of these). Certainly it makes a lot more sense for Starfleet to place the more "conventionally military" units at this level (it also follows UK Naval Service policy for the Royal Marines FWIW) rather than as a very public "top level command" as with the USMC.