Very often, both in this forum, and on comments to my YouTube videos, people will talk about how "hand-size reducing" cards combine well with "draw up to" cards like Jack of all Trades and Watchtower. But it only takes a little thought to see how most of these claims really don't hold any water.
The claim usually goes something like this: Playing a +1 Action card that does not have a +Cards component (like Forager, Fishing Village, or Bag of Gold) goes well with "draw up to" cards because they decrease your handsize. While this is technically true, the end result of this play is no different than playing a cantrip before the "draw up to" card. Let's look at two cards whose only difference is that one of them has a +1 Card: Necropolis and Village. If I, from a 5-card hand, play Necropolis, then Watchtower, I will draw three cards, and still have 1 Action remaining. If I play Village first, drawing one card, and then play Watchtower, this time I will draw two cards. To some, this means that Watchtower was less effective. But the end result is the same - I still ended up drawing three cards, and what's more, they're the same three cards in both cases. In the context of "draw up to" cards, it does not make any difference whether you play a cantrip or a non-drawing non-terminal before it - the result is the same. So saying things like "Festival combos well with Library" really holds very little water.
The one instance where non-drawing non-terminals are better than cantrips is with Menagerie, since instead of "drawing up to", it instead activates at maximum hand variety, which is a lot easier to accomplish when you're not drawing new cards.
But there are other ways to reduce your hand size. Let's look at the prime example of this - Oasis. Oasis is a cantrip, so at first glance it might seem neutral to "draw up to" cards. But because it discards a card, it decreases your handsize. Let's compare Oasis to Peddler, as the only difference between the two is that Oasis discards. If I play Peddler from a 5-card hand, drawing one card, then a Watchtower, I draw two further cards, giving me three total new cards. But if I play Oasis, drawing one card and discarding one card, then a Watchtower, I'll draw three further cards, giving me four total new cards. My handsize is the same now in both cases, but I have one additional card drawn because I played Oasis instead of Peddler.
Perhaps what is trying to be said is that "draw up to" cards work best when they're doing most of the drawing - otherwise, why even buy them? Well, you'll buy them if they're the only way to increase your handsize. I'm not saying that "draw up to" cards aren't perhaps doing a little more work with non-drawing non-terminals - I just think it's silly to assume that your end result (which honestly, is all that matters) will be any different.
Moral of the story - decreasing your handsize by playing cards is essentially neutral to "draw up to" cards, at least when compared to cantrips. The only means of decreasing your handsize in a relevant way to these cards is by discarding.