I recently put a set of CrossMarks on the 26". Only for a laugh, and because I ran them many years ago.I've used an Ikon on the rear of my 26" wheeled hardtail.
I've also run an Ardent Race on the front.
An awesome combination - the Ikon on the back rolls fast and grips well but because of its smaller tread knobs, it can be shaken and you have to be careful braking. It can also wear fairly quickly.
The Ardent Race has a very similar tread pattern to the Ikon but the knobs are bigger than the Ikon and grip much better, particularly if you get the 3C version. It is lighter and rolls faster than the standard Ardent.
I have raced on this combo and also spent general trail time on it as well.
But I wanted something that still rolls well but is grippier than the Ikon and so I'm putting an Ardent Race on the back too for my next race tomorrow.
Post race Edit: the AR on front and rear is a fantastic combo.
Tonnes more grip in all situations when compared with the Ikon.
Maybe a little slower in a straight line but overall average speed is better (compared over two XCO races on the same course) because of the superior grip and confidence it inspires.
BTW, I run tubed with 27psi on the back and 23psi on the front.
Not a bad tire actually.