Hey guys, I have a question for you. I was looking at some magic items that would have been useful to my Gloom Stalker Ranger, and I was interested in the Moon Sickle but when i added it to my inventory and attuned to it, the spell DC of the spells from my subclass, like fear and seeming, didn't increase. Now I know that the Moon Sickle only applies to Druid and Ranger spells, but Gloom Stalker Magic clarifies that those added spells count as Ranger spells for you, so should the DC of those spells increase as well as the others from the Ranger spell list, like Entagle or Searing Smite? Or I am mistaken and the Moon Sickle doesn't apply its bonuses to any other spell besides of the ones on the Druid and Ranger spell list?

It seems to be that D&D beyond does not show updates to non-druid/ranger spells for subclasses. I just tested with Fey Wander, Horizon Walker, and Gloom Stalker. The spells that already appear on the Druid list (charm person) seem to change, but the ones that don't (fear, banishment) seem to stay fixed.

I will also note that these spells also do not list the ranger subclasses in the list they show as "Available For" so I wonder if that is the issue or of the issue is with the item itself.

Thanks, I would like to know anyway if I should just treat those spells as Ranger spells and thefore increase their CD with the Moon Sickle. 

As the Gloom Stalker Magic feature says:

"Starting at 3rd level, you learn an additional spell when you reach certain levels in this class, as shown in the Gloom Stalker Spells table. The spell counts as a ranger spell for you, but it doesn’t count against the number of ranger spells you know."

They are ranger spells and should be treated as such.