Finding high-quality willow x player stuff can be surprisingly tricky because the pairing exists in that weird space between popular fandom and super niche game-specific romance. I wasted hours sifting through general gaming tags on Ao3 before I figured out a better method.
Your absolute best shot is to go directly to Archive of Our Own and use the filtering magic. Don’t just search 'willow player'—search for the specific game's fandom tag first, like 'Stardew Valley' or whatever game your willow is from. Once you’re in that fandom’s works, use the 'Additional Tags' filter and type 'Player/Willow' or 'Willow/Player' (both formats exist). Then sort by 'Kudos' or 'Comments' to see what the community has already voted up as the cream of the crop.
Cross-checking on Tumblr can help too. Some writers post snippets or links there, and if you find a blog dedicated to that character, they often have curated rec lists. I found a three-chapter slow-burn that way that wasn’t topping the kudos chart but was written with incredible care for willow's dialogue from the game.