Trying to be a bird
It's still possible to do it, but more importantly you can do more than just durdle. There's been a number of "win if your life is X" cards out there, and a current standard deck, while not lifegain focused, has a very similar gameplay.I had a "neverending increasing life" deck once, but it relied on some very old (and powerful) cards.
Roughly, it went like this.
1) Play Library of Leng (no hand limit) and Ivory Tower (Gain 1 life for each card beyond 4)
2) Cast Braingeyser (2B + X, draw X cards)
3) Obtain about 20 life a round, with enough counterspells to stop any attempt to break this effect.
4) If you run out of cards, play TimeTwister (Shuffle your Library, Graveyard and Hand together into a new Library, draw 7 new cards, then discard TimeTwister)
5) Use Relearn (take a Sorcery card from you graveyard to your hand) to take TimeTwister into your hand again.
Done right, the deck will a) never run out of cards unless you manage to exile TimeTwister or Relearn and b) give you so much life they needed to force them to lose in some other way. I only played it as an example deck, and I used 3 ten sided dice to represent life. I think I got to 200+ life once
Technically not a loop of cards, but a deck that never runs out of cards and gets you life (and in some cases a lot of life) every round