I think the X-wing has seen a resurgence with younger fans too, after Poe's high-flying feats.
They've also seen some nice action in The Mandalorian. I can't wait to see the Razorcrest get bodied by them (assuming its them from the preview.)
Also, the Ghost from Rebels is quite popular with the younger crowd, although my feelings of it are are similar to my feelings for the Razorcrest...kinda meh...
If I had to pick 3rd one, it would be the A-wing. Very cool, capable fighter, the design for which was inspired by the F-14 Tomcat, I think.