I found a combo while making a deck that is really fun.
Have [[The Gitrog Monster]] and [[Wild Mongrel]] on the battlefield, with [[Dakmor Salvage]] in hand.
Discard Dakmor with Mongrel
When the Gitrog draw trigger happens, dredge Dakmor
Rinse and repeat.
Infinitely large Mongrel, Infinite card draw, and infinite self mill. I recommend having [[Kozilek, Butcher of Truth]], [[Ulamog, the Infinite Gyre]], or [[Emrakul, the Aeons Torn]] just so that you can shuffle your graveyard into your library so that you don't mill yourself to death.
Play Ornithopter/Memnite with a Skullclamp, a Pia's Revolution, and a Puresteel Paladin with active Metalcraft on the battlefield
Attach Skullclamp to the Ornithopter/Memnite.
Pia's Revolution either returns it to your hand, or does 3 damage to your opponent.
If returned to your hand, play it again.
Repeat for infinite ETB triggers
If they take 3 damage, have a Myr Retriever or some other graveyard retrieval spell ready.
I don't know whether anyone has posted this combo yet but
Melira+Cauldron of souls/Caulron haze+any creature with a ETB trigger+sac outlet
1:Have Melira, Cauldron, a sac outlet, and a creature with a ETB trigger out.
2:Tap cauldron to give ETB creature persist.
3:Sac creature. Whenever it comes back, it gets a -1/-1 counter, which is negated by Melira. It still has persist.
4:Repeat
This also works with Mikaeus, the Unhallowed
AFAIK, that doesn't work. Once the creature has returned to play, it is a new entity and therefore no longer has persist.
You could add Dross Scorpion so that every time you sac it, it untaps Cauldron. Then continue this over and over.
[quote from="razzliox »" url="http://www.mtgsalvation.com/forums/the-game/commander-edh/610850-infinite-combos-and-strong-synergies-now-under-new?comment=18"] Jarad, Golgari Lich Lord + Phyrexian Devourer = Each opponent loses life equal to the total CMC of your deck. Technically non-infinite but I think we can call it an infinite combo. In a similar vein, Jarad + Lord of Extinction. Maybe throw those under commander-specific.
AFAIK Jarad and Devourer wouldn't work because Devourer would get too big too fast.
I don't know whether anyone has posted this combo yet but
Melira+Cauldron of souls/Caulron haze+any creature with a ETB trigger+sac outlet
1:Have Melira, Cauldron, a sac outlet, and a creature with a ETB trigger out.
2:Tap cauldron to give ETB creature persist.
3:Sac creature. Whenever it comes back, it gets a -1/-1 counter, which is negated by Melira. It still has persist.
4:Repeat
Have [[The Gitrog Monster]] and [[Wild Mongrel]] on the battlefield, with [[Dakmor Salvage]] in hand.
Discard Dakmor with Mongrel
When the Gitrog draw trigger happens, dredge Dakmor
Rinse and repeat.
Infinitely large Mongrel, Infinite card draw, and infinite self mill. I recommend having [[Kozilek, Butcher of Truth]], [[Ulamog, the Infinite Gyre]], or [[Emrakul, the Aeons Torn]] just so that you can shuffle your graveyard into your library so that you don't mill yourself to death.
Ornithopter/Memnite + Pia's Revolution + Puresteel Paladin (Metalcraft) + Skullclamp
Play Ornithopter/Memnite with a Skullclamp, a Pia's Revolution, and a Puresteel Paladin with active Metalcraft on the battlefield
Attach Skullclamp to the Ornithopter/Memnite.
Pia's Revolution either returns it to your hand, or does 3 damage to your opponent.
If returned to your hand, play it again.
Repeat for infinite ETB triggers
If they take 3 damage, have a Myr Retriever or some other graveyard retrieval spell ready.
You could add Dross Scorpion so that every time you sac it, it untaps Cauldron. Then continue this over and over.
Jarad, Golgari Lich Lord + Phyrexian Devourer = Each opponent loses life equal to the total CMC of your deck. Technically non-infinite but I think we can call it an infinite combo. In a similar vein, Jarad + Lord of Extinction. Maybe throw those under commander-specific.
AFAIK Jarad and Devourer wouldn't work because Devourer would get too big too fast.
Melira+Cauldron of souls/Caulron haze+any creature with a ETB trigger+sac outlet
1:Have Melira, Cauldron, a sac outlet, and a creature with a ETB trigger out.
2:Tap cauldron to give ETB creature persist.
3:Sac creature. Whenever it comes back, it gets a -1/-1 counter, which is negated by Melira. It still has persist.
4:Repeat
This also works with Mikaeus, the Unhallowed