Throughout D2, you will find shrines and wells that will help you in the game in many different ways.  Once you find one, it will always be in the same place, although the type of shrine or well will be be random.  Some shrines recharge after a time, while others (usually the good ones) don't.  The ones that say 'no pic' have no special picture in the game -- they vary from act to act.

 

Pic Name Effect Refills
(no pic) Well Fully refills your health and mana. Yes
(no pic) Refilling Shrine Fully refills your health and mana. Yes
(no pic) Health Shrine Fully refills your health. Yes
(no pic) Mana Shrine Fully refills your mana. Yes
  Mana Recharge Shrine Increases the rate at which your mana recharges by 50%. Yes
Glowing shield Armor Shrine Boosts your armor by 100%. Yes
  Combat Shrine Increases both your attack rating and maximum damage by 200%. Yes
Silver ball in flames (why? i have no idea, but it does look kinda keen)

 

Resist Fire Shrine Increases your resistance to fire by 75%. Yes
  Resist Cold Shrine Increases your resistance to cold by 75%. Yes
  Resist Poison Shrine Increases your resistance to poison by 75%. Yes
  Resist Lightning Shrine Increases your resistance to lightning by 75%. Yes
Glowing hand Skill Shrine Increases all known skills by 2 levels. Yes
  Recharge Shrine Increases the rate at which your mana recharges by 400%. Yes
  Stamina Shrine Gives you unlimited stamina while active. Yes
Glowing flag Experience Shrine Gives you 50% more experience per kill. No
(no pic) Monster Shrine When this shrine is touched, the nearest enemy becomes a unique monster. No
(no pic) Fire Shrine A ring of firebolts explode outward from the shrine, damaging everything in their path, including you, your allies, and your enemies. No
(no pic) Poison Shrine Sends out poison clouds that poison anyone nearby, but also gives you between five to ten Gas potions. No
(no pic) Exploding Shrine This shrine will also cause damage when touched, but will also throw out five to ten Exploding potions. No
(no pic) Gem Shrine Upgrades one gem (selected at random) from your inventory.  If there are no gems in your inventory, it drops a random chipped gem. No