Ancient Tunnels, Lost City (Act 2)The Ancient Tunnels is an old location. The location is essentially a reskin or re-use of the Sewers layout which was constructed under Lut Gholein D2R Ladder Items. That's not a bad thing since that means that it's a great area for enemies to be in. area is extremely high. In addition the Ancient Tunnels contains enemies that don't have Cold Damage or Status Immunity with Hell difficulty.
This is why it's a popular hunting spot, particularly with Blizzard Sorceress creations. After the Dungeon randomly Unique Monsters appear as well as a sparkling treasure chest that has items for the endgame. Again, just make sure to bring Magic Find gear or compensate for the deficiency by repeating the exercise several times.
Arcane Sanctuary (Act 2)To be transparent, the enemies within Arcane Sanctuary are too spread out to make it difficult to find resources. Doing battle with the game's most difficult bosses makes for a better target to kill in order get your hands on loot.
However, once you have found a method for Teleport (either either the Sorceress ability or Enigma Runeword), there are Super Chests there that provide amazing loot that doesn't require fighting. In the Arcane Sanctuary Diablo 2 Resurrected Items, Arcane Sanctuary is an ideal chest farming place for characters that aren't yet able to single-hit their enemies.