Agatha's Soul Cauldron
Lurking Roper
Kwain, Itinerant Meddler

   Prerequisites

What do I need to start this combo?
Kwain in exile (Kwain exiled by Agatha's Soul Cauldron in exile).
Agatha's Soul Cauldron and Lurking Roper on the battlefield.
Lurking Roper has at least one +1/+1 counter on it and does not have summoning sickness.

   Steps

How does this combo work?
1
Activate Lurking Roper using Kwain's ability by tapping it, causing you to draw a card and gain 1 life, and allowing each opponent to do the same.
2
Lurking Roper triggers, untapping itself.
3
Repeat.

   Results

What do I get from this combo?
Infinite card draw for all players
Infinite draw triggers for all players
Near-infinite lifegain for all players
Near-infinite lifegain triggers for all players