Sadly I didn't know either! It wasn't until last night that I was analyzing some raid parses that I notice how well bell toll was doing for a single charm. The. I when I was clearing out my inventory I noticed the new charm. this is probably why people underrate these charms due to the vauge description. Still looking for a new Amhrail ring purse thingy upgrade too.
For a Warlock, you want Salvo III (from Zav) and some sort of Growing Criticals (Growing Criticals III from Highhold, or Growing Criticals IV from Temple) If you don't have EV though, then the Vigor Charm is good.
Mogrim is right, that is, if you can raid those zones. Salvo III charm is called Spiteful Archaic Idol from The Crumbling Icon in Zavithloa: The Molten Pools raid. The Growing Criticals III charm is called Swirling Arachnid Orb from Gomrim / Tonnin / Yermon / Zwebek encounter in Ssraeshza Temple: Echoes of Time raid.