Outside of trivial answers like: hybrid, multiclass, half-elf (especially in paragon), there are some potentially interesting item combinations.
While far more appropriate for an essentials character, a Farslayer Weapon provides an excellent backup-weapon for the monk (with melee training), as monk bonus-damage comes from flurry of blows. The far far more cheesybroken version is the Blade of the Eldrich Knight which provides reach 5 for standard action attacks. A bow (if offered racially) or dagger is not at all a bad backup option. While it's not huge-striker damage, it keeps you contributing to the fight if everyone's ranged. The Fey Strike Weapon is a fantastic "Get Over Here!" pseudo-pull. Magnetic Armor provides a similar service. The Net Snare offers a flavourful grab+pull, though it needs standard forced movement improvement for it to be a useful lockdown for the monk. It synergizes with the net multiclass exceedingly well, however, because slow + grabbed + pull/slide = one unhappy enemy. For that matter, with the World Serpent's Grasp feat, an action point on this netted enemy will knock the flyer prone, and it will be difficult for the flyer to escape the netted slow/grab.
Masterful Spiral + longspear/staff expertise/transcendent ki-focus gives you reach 3. While not a supremely good reach, enemies would have to fly quite high to avoid that. (I'm not sure if staff expertise and the transcendent ki focus sack, I'm pretty sure they don't.
Bracers of Brachiation give you a climb speed which can be handy for lowering the volume of untenable terrain. Technically you can fight while climbing normally, but you don't actually want to engage in combat without a climb speed. The Wilden [Clinging Vines] is one o the better options here.4
At higher levels, it's fairly trivial to gain a fly speed.