[Magic Trivia Showoff Mode]
There’s a long and honorable history of red creatures with protection from red, including the following off the top of my head:
Skirk Fire Marshall
Beast of Bogardan
Subterranean Spirit
Red creatures with pro white include:
Mountain Yeti
Wildfire Emissary
Knight of Thorn? (I think I have that name right)
That’s all I can think of in either category…
a quick check of mtgnews.com reveals that I forgot about the following cards:
Defender of Chaos (pro white)
Keeper of Kookus (built-in ability to gain pro red)
Hell-Bent Raider (built-in ability to gain pro white)
and Knights of Thorn are a white guy with pro red, not the other way around. See what I get for trying to show off? 
oh, and to prove that I haven’t learned my lesson about trying to show off, ways to kill (or at least neutralize) Iridescent Angel include:
-Wrath of God (sorcery, bury all creatures) and it’s ilk
-Jokulhaups (sorcery, bury creatures, artifacts, and lands) and it’s ilk
-Void (sorcery, pick a casting cost and destroy everything of that cost)
-Whirlwind (sorcery, destroy all creatures with flying)
-Various global color-hosers (Anarchy, a sorcery that destroys all white permanents, being the most efficient)
-Diabolic Edict, Chainer’s Edict, Gravepact, Abyssal Gatekeeper, Urborg Justice, Do or Die, Innocent Blood, and Cabal Executioner (effects that make a player sacrifice a creature)
-Creature-type hosers, such as Tsabo’s Decree, Extinction, and oh-so-classy An-Zerrin Ruins
-Harbinger of Night (a black creature who puts a -1/-1 counter on every creature in play every turn)
-Ways to turn your permanent’s colorless, including (as mentioned by vandal), Ghostly Flame and Thran Lens. Plus Ersatz Gnomes. And with Erstatz Gnomes and deflection, you can play all sorts of tricks…
-Global enchantments that hose flyers, such as two copies of Katabatic Winds, or two copies of crosswinds
-Circles or runes of protection
-Ways to temporarily gain control of all of your opponent’s creatures, with you then might find a way to sacrifice (Insurrection and Reins of Power)
-Thieve’s Auction (a wacky sorcery which redistributes all the permaments on the table)
-Artifact creatures, including large artifact flyers (Teeka’s Dragon, Flowstone Sculpture, Flowstone Thopter, Copper-Leaf Angel, and Lotus Guardian)
-Artifacts that tap it, such as Icy Manipulator, Ring of Gix, and Amber Prison
-Artifacts that won’t let it untap, attack, or deal damage, such as Meekstone, Ensnaring Bridge, Horn of Deafening or Barl’s Cage
-A very small number of artifacts that will outright remove it from play, such as Amulet of Unmaking, Sandstone Deadfall, Whirling Catapault, Nevinyrral’s disk, powder keg, and (my personal favorite) Tawnos’s Coffin
-And finally, best of all, an artifact that allows you to gain control of it, namely, Helm of Possession
[/Magic Trivia Showoff Mode]