Foul Watcher - There's been zero discussion on this card, but I'm intrigued enough to try it. I like surveil for card filtering, it fits with flying decks and ETB decks, and it can also set up graveyard recursion.
I am not an native English speaker so I might not understand the word niche as I thought I did but Tireless Provisioner is not as niche as Evolution Sage, right? Both require you to play lands, but Sage requires you to have counters on things as well while Provisioner gets value out of the land drops regardless of board state. Of the two, Sage is more niche almost by default. It could be stronger in the right deck, sure, but that's not what niche means or have I just been using this word wrong?
You've got the word correct. IMO wanting to conditionally ramp on a 3 drop and/or wanting to gain life at the cost of mana are both fairly weak effects. No one is going to turn down a free food token, but it takes specific scenarios for those to be actively good (as opposed to just "okay") and therefore takes a specific deck for me to want it. In my mind that makes it niche, though I understand why other people might not see it that way.
Big fan of the Vile Gravedigger. It's the kind of card that enables high-synergy decks without being embarrassing in lower synergy builds. In some decks he is a flexible tutor for a reanimation target or an unburial rites, while in others he just finds a decent GY value spell like Reach of Branches.
I'm bigger on Herd Baloth than others. I've been trying to support +1/+1 synergy for years, and it's easier to get counters on this guy than you might think. For instance Llanowar Reborn makes this guy a 5 mana 4/4 + 5/5 with upside. That's nothing to sneeze at.