I tested all of them, but don't have the spreadsheet anymore. All of these are subject to me possibly remembering it wrong, or potential changes since I tested. Corrections are welcome, but these are what I use and never have issues with voyria.
All of them are hidden to everyone in the room with the exception of Dagaz, and heal everything that can be cured by tree tattoo, with the exception of Purity.
Panacea: flat 10 second tic, ~2 minute duration
Necklace of Purity: flat 10 second tic, venom affs only, no drain/essence use whatsoever (making it the best passive in the game)
RoH: random interval between 7 and 20 seconds (ballpark) - costs Devotion and only sticks to a single room.
Angel Care random interval between 15 and 45 seconds (ballpark) - Heavy angel power drain, and does not stack with RoH. RoH overrides Angel Care if both are active.
Hallelujah: I forget, but I think it's random interval and around 15 seconds. Static to a room, but can be summoned
Dagaz: 15 second static, has 3rd person message.
Demon Syphon: I don't remember, but likely identical to Angel Care.
Note that most passives in the game are random. This is bad for people using them since it makes them unreliable (and generally, slower), and bad for people trying to keep track of afflictions, since you have absolutely no way of knowing when they proc.
If maintaining voyria is your primary concern, the two best options are to either just guess with it, or to use Expert Diagnose to check every so often. If you're really good (or use Godzilla) you can track their balances, including sip balance, and note when they sip elixirs while off sip balance, indicating an immunity sip. You can also track health/mana vial type with pretty good accuracy, if your opponent doesn't have vials of identical type.
No, taking about continious passive cures for locking purposes. Demon siphon is like every 6 or 8 seconds if I remember. Anyone have all the numbers?
i think one of the runes does it less predictably
Dagaz used to be random, but was changed to a consistent tick in the September classleads. One per 15 seconds, according to @Kenway. Don't know about any others offhand.
Answers
It also only cures pacifying afflictions. Not sure what that's worth to you.
i think one of the runes does it less predictably
Worth noting that RoH and Angel Care (and therefore demon syphon) are arguably the worst passives in the game, contrary to popular opinion.
Hallelujah is actually pretty bad, too. It's random, so no exact time period.
Dagaz is, ironically, one of the best now. Necklace of purity is easily the best, though.