Say you have a {Boros Reckoner} and an {Archangel of Thune} out and you do the infinite life loop, does that make the Angels ability trigger every time so that you have a crazy amount of +1/+1 counters?
Yes, and furthermore, you don't need to give your reckoner indestructible if you just deal 1 damage to it somehow. You can stack the triggers so that boros reckoner gets a counter before he is dealt the next damage:
You have {Archangel of Thune} and a {Boros Reckoner} on the field. You swing with reckoner and your opponent blocks with an {Arbor Elf}. Before the damage step, you cast {Azorius Charm} to give your guys lifelink. Here is what you can do:
Damage step:
Boros reckoner is dealt 1 damage by the arbor elf, and you gain 3 life because the boros reckoner dealt 3 to the arbor elf. Since you gain life at the same time boros reckoner takes damage, {Archangel of Thune} and {Boros Reckoner}'s abilities trigger at the same time. Since you control both triggers, you decide which resolves first. Have the reckoner's trigger first so the archangel's trigger resolves first. You do this over and over, so boros reckoner gets a 1/1 counter before he deals 1 damage to himself over and over.
Well that's pretty amazing lol I'm going to build that deck for sure