My 4e game has seen a fair bit of ritual use, but I'm not familiar with Comrade's Succour. The name suggests it's for moving healing surges around - is that right?'That was the main one of course. Some others that fall into the "you will be assumed to have access to this" would be Phantom Steed, Speak With Dead, Raise Dead, Tenser's Floating Disk, Enchant Magic Item, Disenchant Magic Item. Its not that you can't do without them, but any adventure that doesn't properly anticipate their use will run into problems, so they generally become close to mandatory.
Phantom Steed sees a lot of use in our game.
Speak with Dead has never been used.
Raise Dead has been used a few times (but moslty by NPCs), Tenser's Floating Disc a few times, and Enchant/Disenchant on occasion (but not that often - I tend to give out items directly via wish list than have the PCs make them out of gold in the fiction).
Object Reading has been popular in our game, and Hallowed Temple (for taking extended rests in dangerous places), Endure Elements (for travelling through dangerous places), Wizard's Curtain (for stealthing the party), Seeming (ditto), and others I can't recall off the top of my head! (OK, just recalled one - Remove Affliction. A good cure-all ritual.)